JP7169595B2 - Rotating electric machine controller - Google Patents

Description

The present invention relates to a rotary electric machine control device that drives and controls a rotary electric machine having open windings via two inverters.

In the IEEE paper "Dual Inverter-Fed Traction Drive with DC Sources Power Balancing Based on Synchronized PWM" by V. Oleschuk et al. A control device is disclosed that drives and controls a rotating electrical machine by switching-controlling inverters provided one by one. On the other hand, as a well-known form, for example, one inverter is switching-controlled to the other end of a Y-shaped winding to which one end of each of three-phase windings is connected to control the driving of a rotating electric machine. In a system with an open winding and two inverters, if the DC voltage is the same, the line-to-line voltage of the AC voltage in the windings is higher than in a system with a Y-shaped winding and one inverter. and the rotating electric machine can be operated at a higher output.

In the introduction of the paper by V. Oleschuk et al., the magnitude of the ripple in the current flowing through the windings is reduced by differentiating the phases of the carrier signals that generate the pulses for controlling the switching of the two inverters. It states what you can do. V. Oleschuk et al. also note that generating pulses synchronously rather than asynchronously with a carrier signal allows better control even for medium/high power applications. there is However, in both the asynchronous system and the synchronous system, the two inverters are always switching-controlled by the same control system.

V. Oleschuk, R. Bojoi, G. Griva, F. Profumo, “Dual Inverter-Fed Traction Drive with DC Sources Power Balancing Based on Synchronized PWM,” Conference Paper/June 2007, 1-4244-0743-5/07, IEEE, p.260-265

The switching control method should be determined by various factors (operating conditions), such as the torque required for the rotating electrical machine, rotational speed, and voltage on the DC side, so that operation with higher system efficiency is possible. is preferred. Although the technique of V. Oleschuk et al. is excellent, there is still room for improvement in properly controlling the two inverters provided at both ends of the open winding.

In view of the above background, it is desired to provide a technique for appropriately controlling the two inverters provided at both ends of the open winding.

In view of the above, a rotating electrical machine control device that drives and controls a rotating electrical machine having open windings of a plurality of phases that are independent of each other via a first inverter and a second inverter has, as one aspect, the first inverter comprising: It is connected to one end of the open windings of multiple phases to convert power between direct current and alternating current of multiple phases, and the second inverter is connected to the other end of the open windings of multiple phases. Power is converted between direct current and multi-phase alternating current, and each of the first inverter and the second inverter can be controlled by a plurality of control systems with different switching patterns, and the control systems are independent of each other. The control method includes pulse width modulation control in which a plurality of pulses with different patterns are output in one cycle of the electrical angle, and rectangular wave control in which one pulse is output in one cycle of the electrical angle. One of the first inverter and the second inverter is controlled by the rectangular wave control, and the other inverter is controlled by special pulse width modulation control, which is one of the pulse width modulation controls. Target control is executed, and the special pulse width modulation control is switching based on a difference between a switching pattern by the pulse width modulation control when a target voltage is generated in the open winding and a switching pattern by the square wave control. It is the said control method used as a pattern.

According to this configuration, one of the two inverters is subjected to rectangular wave control, thereby reducing the number of switching times of the one inverter and reducing the switching loss. The other inverter, which is not subjected to square wave control, is controlled by special pulse width modulation control. In the special pulse width modulation control, the other inverter is controlled by a switching pattern based on the difference between the switching pattern by the pulse width modulation control when generating the target voltage in the open winding and the switching pattern by the rectangular wave control. be. Therefore, even if one inverter is controlled by rectangular wave control, the rotary electric machine can be driven smoothly by combining the pulse width modulation control of the other inverter. In general, system loss can be reduced and the rotating electric machine can be smoothly controlled in a relatively high rotation operating region where square wave control is applied. That is, according to this configuration, it is possible to appropriately control the two inverters provided at both ends of the open winding.

Further features and advantages of the rotating electrical machine control device will become clear from the following description of the embodiments described with reference to the drawings.

Schematic block diagram showing an example of a rotary electric machine drive system A simple partial block diagram of a rotary electric machine control device Vector diagram of a rotary electric machine drive system using two inverters Schematic voltage vector diagram of rotating electric machine in orthogonal vector space A diagram showing an example of a control region of a rotating electric machine A diagram showing an example of a control region of a rotating electric machine A diagram showing an example of a control region of a rotating electric machine Waveform diagram showing an example of voltage commands and switching control signals for special pulse width modulation control (special continuous pulse width modulation control) Waveform diagrams showing examples of voltage commands and switching control signals for special discontinuous pulse width modulation control Explanatory diagram showing the voltage command calculation principle (result) of special continuous pulse width modulation control Explanatory diagram showing the voltage command calculation principle (progress 1) of special continuous pulse width modulation control Explanatory diagram showing the voltage command calculation principle (progress 2) of special continuous pulse width modulation control Explanatory diagram showing the voltage command calculation principle (progress 3) of special continuous pulse width modulation control Explanatory diagram showing the voltage command calculation principle (result) of special discontinuous pulse width modulation control Explanatory diagram showing the voltage command calculation principle (progress 1) of special discontinuous pulse width modulation control Explanatory diagram showing the voltage command calculation principle (progress 2) of special discontinuous pulse width modulation control Explanatory diagram showing the voltage command calculation principle (progress 3) of special discontinuous pulse width modulation control Flowchart showing an example of a voltage command calculation procedure for special pulse width modulation control Flowchart showing another example of voltage command calculation procedure for special pulse width modulation control Waveform diagram of 3-phase current and dq-axis current when rectangular wave control and normal continuous pulse width modulation control (CPWM) are combined in the first high-speed region Waveform diagram of three-phase current and actual modulation factor when square wave control and normal continuous pulse width modulation control (CPWM) are combined in the first high-speed region Waveform diagram of 3-phase current and dq-axis current when rectangular wave control and normal pulse width modulation control (CPWM, DPWM) are combined in the first and second high-speed regions Waveform diagram of 3-phase current and actual modulation factor when rectangular wave control and normal pulse width modulation control (CPWM, DPWM) are combined in the first and second high-speed regions Waveform diagram of 3-phase current and dq-axis current when rectangular wave control and special continuous pulse width modulation control (SP-CPWM) are combined in the first high-speed region Waveform diagram of three-phase current and actual modulation factor when rectangular wave control and special continuous pulse width modulation control (SP-CPWM) are combined in the first high-speed region Waveform diagram of three-phase current and dq-axis current when rectangular wave control and special pulse width modulation control (SP-CPWM, SP-DPWM) are combined in the first and second high-speed regions Waveform diagram of three-phase current and actual modulation factor when square wave control and special pulse width modulation control (SP-CPWM, SP-DPWM) are combined in the first and second high-speed regions Waveforms of 3-phase current and dq-axis current when rectangular wave control and special pulse width modulation control (SP-CPWM, SP-DPWM) are combined by increasing the carrier frequency in the first and second high-speed regions figure Waveforms of 3-phase current and actual modulation factor when rectangular wave control and special pulse width modulation control (SP-CPWM, SP-DPWM) are combined with carrier frequency increased in the first and second high-speed regions figure Waveform diagram showing an example of voltage commands and switching control signals in the ultra-high speed range Waveform diagram showing an example of voltage commands and switching control signals in a low speed range (first low speed range) Waveform diagram showing an example of voltage commands and switching control signals in the second low speed region Waveform diagram showing other examples of voltage commands and switching control signals in the intermediate speed range Waveform diagram showing an example of voltage commands and switching control signals for mixed pulse width modulation control Waveform diagrams showing other examples of voltage commands and switching control signals for mixed pulse width modulation control Schematic block diagram showing another example of a rotary electric machine drive system Schematic block diagram showing another example of a rotary electric machine drive system A diagram showing an example of a control region of a rotating electric machine in a one-inverter system.

An embodiment of a rotary electric machine control device that drives and controls a rotary electric machine having open windings of a plurality of phases independent of each other via two inverters will be described below with reference to the drawings. FIG. 1 is a schematic block diagram of a rotating electrical machine drive system including a rotating electrical machine control device 1 (MG-CTRL). The rotating electric machine 80 is, for example, a driving force source for wheels in a vehicle such as an electric vehicle or a hybrid vehicle. The rotary electric machine 80 is an open winding type rotary electric machine having stator coils 8 (open windings) of a plurality of phases (three phases in this embodiment) that are independent of each other. Each end of the stator coil 8 is connected to one inverter 10 that is independently controlled and converts power between a direct current and a plurality of phases (here, three phases) of alternating current. That is, one end of the stator coil 8 is connected to the first inverter 11 (INV1), and the other end of the stator coil 8 is connected to the second inverter 12 (INV2). In the following description, the first inverter 11 and the second inverter 12 are simply referred to as the inverter 10 when there is no need to distinguish between them.

Inverter 10 is configured to have a plurality of switching elements 3 . As the switching element 3, an IGBT (Insulated Gate Bipolar Transistor) or a power MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is used. FIG. 1 exemplifies a mode in which a Si-IGBT is used as the first switching element 31 of the first inverter 11 and a SiC-MOSFET is used as the second switching element 32 of the second inverter 12 . The first switching element 31 may be Si-MOSFET instead of Si-IGBT. The second switching element 32 may be SiC-SIT (SiC-Static Induction Transistor), GaN-MOSFET (Gallium Nitride-MOSFET), or the like, in addition to SiC-MOSFET. That is, in the present embodiment, the second switching element 32 that forms the second inverter 12 is more stable than the first switching element 31 that forms the first inverter 11 at the time of transition between the off state and the on state. A switching element with a relatively small switching loss is preferable.

Since SiC semiconductors and GaN semiconductors are generally more expensive than Si semiconductors, the present embodiment exemplifies a form in which a SiC semiconductor is used for the switching element 3 that constitutes one of the two inverters 10. . However, if the prices of SiC semiconductors and GaN semiconductors drop due to mass production effects, etc., both inverters 10 may be made of SiC semiconductors (for example, SiC-MOSFETs), as shown in FIG. . Also, both inverters 10 may be made of Si semiconductors (eg, Si-IGBTs) as shown in FIG.

In each of the two inverters 10, an arm 3A for one phase of alternating current is configured by a series circuit of an upper switching element 3H and a lower switching element 3L. Each switching element 3 is provided with a freewheel diode 35 in parallel with the direction from the negative electrode FG to the positive electrode P (the direction from the lower side to the upper side) as the forward direction. Moreover, in this embodiment, the two inverters 10 are connected to independent DC power sources 6 respectively. That is, the first floating ground FG1, which is the negative electrode FG of the first inverter 11, and the second floating ground FG2, which is the negative electrode FG of the second inverter 12, are independent of each other. A DC link capacitor 4 (smoothing capacitor) for smoothing a DC voltage is provided between the inverter 10 and the DC power supply 6 .

Specifically, the first inverter 11, in which the arm 3A for one AC phase is configured by a series circuit of a first upper-stage switching element 31H and a first lower-stage switching element 31L, has a first DC link capacitor on the DC side. 41 (first smoothing capacitor) is connected, the DC side is connected to the first DC power supply 61, and the AC side is connected to one end side of the multi-phase stator coil 8, so that between the DC and the multi-phase AC Convert power. The second inverter 12, in which the AC one-phase arm 3A is configured by a series circuit of a second upper-stage switching element 32H and a second lower-stage switching element 32L, has a second DC link capacitor 42 (second smoothing capacitor) on the DC side. A capacitor) is connected, the DC side is connected to the second DC power supply 62, and the AC side is connected to the other end side of the multi-phase stator coil 8 to convert power between DC and multi-phase AC. .

In this embodiment, the first DC power supply 61 and the second DC power supply 62 are DC power supplies having the same ratings such as voltage. That is, the rated voltage "E1" of the first DC power supply 61 and the rated voltage "E2" of the second DC power supply 62 are the same, and are simply referred to as the rated voltage "E" when they are not distinguished from each other. Therefore, the DC side voltage (DC link voltage) "Vdc1" of the first inverter 11 and the DC side voltage (DC link voltage) "Vdc2" of the second inverter 12 are the same voltage. Also, the first DC link capacitor 41 and the second DC link capacitor are capacitors having equivalent ratings such as capacity. The rated voltage of the DC power supply 6 is about 48V to 400V. The DC power supply 6 is composed of, for example, a secondary battery (battery) such as a nickel-metal hydride battery or a lithium ion battery, an electric double layer capacitor, or the like. The rotating electric machine 80 can function as both an electric motor and a generator. Rotating electric machine 80 converts electric power from DC power supply 6 into motive power via inverter 10 (powering). Alternatively, the rotating electric machine 80 converts the rotational driving force transmitted from the wheels or the like into electric power, and charges the DC power supply 6 via the inverter 10 (regeneration).

As shown in FIG. 1 , inverter 10 is controlled by rotary electric machine control device 1 . The rotary electric machine control device 1 can control each of the first inverter 11 and the second inverter 12 by a control method independent of each other (details of the control method will be described later). The rotary electric machine control device 1 is constructed with a logic circuit such as a microcomputer as a core member. For example, the rotating electrical machine control device 1 performs current feedback control using a vector control method based on a target torque (torque command) for the rotating electrical machine 80 provided from another control device such as a vehicle control device (not shown). and controls the rotating electric machine 80 via the inverter 10 .

An actual current flowing through the stator coil 8 of each phase of the rotating electrical machine 80 is detected by the current sensor 15, and the magnetic pole position of the rotor of the rotating electrical machine 80 at each time is detected by the rotation sensor 13 such as a resolver. The rotary electric machine control device 1 uses the detection results of the current sensor 15 and the rotation sensor 13 to perform current feedback control. The rotary electric machine control device 1 is configured with various functional units for current feedback control, and each functional unit is realized by cooperation of hardware such as a microcomputer and software (program). be.

The block diagram of FIG. 2 simply shows some functional units of the rotary electric machine control device 1 . In the vector control method, the actual currents (U-phase current Iu, V-phase current Iv, W-phase current Iw) flowing in the rotating electrical machine 80 are controlled by the direction of the magnetic field (flux) generated by the permanent magnets arranged in the rotor of the rotating electrical machine 80. and the vector component (d-axis current Id, q-axis current Iq) of the d-axis and the q-axis in the direction orthogonal to the d-axis (the direction leading π/2 in electrical angle with respect to the direction of the magnetic field). feedback control. The rotary electric machine control device 1 performs coordinate conversion in the three-phase two-phase coordinate conversion section 55 based on the detection result (θ: magnetic pole position, electrical angle) of the rotation sensor 13 .

The current feedback control unit 5 (FB) outputs a current command (d-axis current command Id ^* , q-axis current command Iq ^* ) based on the torque command of the rotary electric machine 80 and an actual current (d-axis The rotary electric machine 80 is feedback-controlled based on the deviation from the current Id and the q-axis current Iq) to calculate voltage commands (d-axis voltage command Vd ^* , q-axis voltage command Vq ^* ). Rotating electric machine 80 is driven via two inverters 10 , a first inverter 11 and a second inverter 12 . Therefore, the d-axis voltage command Vd ^* and the q-axis voltage command Vq ^* are distributed to the first d-axis voltage command Vd1 ^* and the first q-axis voltage command Vq1 ^* for the first inverter 11 in the distribution unit 53 (DIV), respectively. It is distributed to the second d-axis voltage command Vd2 ^* and the second q-axis voltage command Vq2 ^* for the two inverters 12. As described above, in the present embodiment, the DC link voltage "Vdc1" of the first inverter 11 and the DC link voltage "Vdc2" of the second inverter 12 are the same voltage (Vc1=Vdc2). Therefore, the distributed voltage commands are also "Vd1 ^* =Vd2 ^* " and "Vq1 ^* =Vq2 ^* ".

As described above, the rotary electric machine control device 1 can control the first inverter 11 and the second inverter 12 by mutually independent control methods, and the three-phase voltage command calculation unit 73 and the modulation unit 74 (MOD ) are provided. That is, the rotary electric machine control device 1 includes a first voltage control unit 71 that generates switching control signals (Su1, Sv1, Sw1) for each of the U-phase, V-phase, and W-phase of the first inverter 11, and a second voltage control section 72 that generates switching control signals (Su2, Sv2, Sw2) for the U-phase, V-phase, and W-phase, respectively. ^{Details will} be described later with ^reference to ^FIGS . , Vv2 ^** , Vw2 ^** ) are different from each other by “π”. Therefore, a value obtained by subtracting “π” from the detection result (θ) of the rotation sensor 13 is input to the second voltage control unit 72 .

As shown in FIG. 2, the second voltage control unit 72 includes a three-phase voltage command calculation unit 73 and a modulation unit 74 that are connected in the same manner as the first voltage control unit 71. In addition, another three-phase voltage command It has a calculation section 73 (special modulation three-phase voltage command calculation section 73 B), a modulation section (special modulation modulation section 75 ), and a selection section 76 . In the second voltage controller 72, the selector 76 selects the normal-modulated switching control signal generated by the modulator 74 and the special-modulated switching control signal generated by the special-modulation modulator 75. They are output as switching control signals (Su2, Sv2, Sw2) for the inverter 12 . This special modulation is a special pulse width modulation to be described later, and the details will be described later with reference to FIGS. 8 to 19 and the like. Note that the control block is not limited to this configuration. The switching control signals (Su2, Sv2, Sw2) for the second inverter 12 may be generated by a common modulation section based on the voltage command.

As will be described later, modulation methods include synchronous modulation synchronized with the rotation of the rotating electrical machine 80 and asynchronous modulation independent of the rotation of the rotating electrical machine 80 . In general, a switching control signal generation block by synchronous modulation (a generation flow in the case of software) is different from a switching control signal generation block by asynchronous modulation. The voltage control unit 7 described above generates a switching control signal based on a voltage command and a carrier that is not synchronized with the rotation of the rotating electric machine 80. A switching control signal by modulation (for example, a switching control signal in the case of rectangular wave control, which will be described later) is also generated by the voltage control unit 7 in the following description.

As described above, each arm 3A of the inverter 10 is configured by a series circuit of the upper switching element 3H and the lower switching element 3L. Although not distinguished in FIG. 2, the switching control signal for each phase is output as two types, an upper stage switching control signal and a lower stage switching control signal. For example, the first U-phase switching control signal Su1 for controlling the switching of the U-phase of the first inverter 11 includes the first U-phase upper-side switching control signal Su1+ with "+" at the end and the first U-phase switching control signal Su1+ with "-" at the end. It is output as two signals, ie, the 1U-phase lower stage switching control signal Su1−. When the upper switching element 3H and the lower switching element 3L constituting each arm 3A are turned on at the same time, the arm 3A is short-circuited. To prevent this, a dead time is provided during which both the upper-side switching control signal and the lower-side switching control signal for each arm 3A are in an ineffective state. This dead time is also added in the voltage control section 7 .

As shown in FIG. 1, the control terminals (gate terminals in the case of IGBTs and FETs) of the switching elements 3 constituting the inverter 10 are connected to the rotary electric machine control device 1 via the drive circuit 2 (DRV). , are individually switching controlled. A high-voltage system circuit (system connected to the DC power supply 6) for driving the rotating electric machine 80 such as the inverter 10, and a low-voltage system circuit (from 3.3 volts to The operating voltage (the power supply voltage of the circuit) is greatly different from the operating voltage system of about 5 volts. The drive circuit 2 relays a drive signal (switching control signal) for each switching element 3 after increasing its drive capability (for example, voltage amplitude, output current, or the like, ability to operate a circuit at a later stage). The first drive circuit 21 relays the switching control signal to the first inverter 11 and the second drive circuit 22 relays the switching control signal to the second inverter 12 .

The rotary electric machine control device 1 has a switching pattern form (voltage waveform control form) of the switching elements 3 constituting the first inverter 11 and the second inverter 12, for example, a plurality of pulses with different patterns in one cycle of the electrical angle. Execution of pulse width modulation (PWM) control for output and rectangular wave control (1-Pulse) for outputting one pulse in one cycle of electrical angle. can be done. That is, the rotary electric machine control device 1 can perform pulse width modulation control and rectangular wave control as control methods for the first inverter 11 and the second inverter 12 . Note that, as described above, the rotary electric machine control device 1 can control the first inverter 11 and the second inverter 12 by control methods independent of each other.

Pulse width modulation includes continuous pulse width modulation (CPWM), such as sinusoidal pulse width modulation (SPWM) and space vector pulse width modulation (SVPWM), and discontinuous pulse width modulation (CPWM). There are methods such as modulation (DPWM: Discontinuous PWM). Therefore, the pulse width modulation control that can be executed by the rotary electric machine control device 1 includes continuous pulse width modulation control and discontinuous pulse width modulation as control methods.

Continuous pulse width modulation is a modulation method in which pulse width modulation is continuously performed for all of the arms 3A of multiple phases, and discontinuous pulse width modulation is a modulation method in which switching elements are turned on or off for some arms 3A of multiple phases. This is a modulation method that performs pulse width modulation including a fixed state period. Specifically, in discontinuous pulse width modulation, for example, the signal level of a switching control signal for an inverter corresponding to one phase of three-phase AC power is sequentially fixed, and switching control signals corresponding to the other two phases are fixed. Vary the signal level of the In continuous pulse width modulation, all phases are modulated without such a fixed switching control signal corresponding to any phase. These modulation methods are based on operating conditions such as rotational speed and torque required of the rotating electric machine 80, and the modulation rate (effective value of the three-phase AC line voltage with respect to the DC voltage) required to satisfy the operating conditions. percentage).

In pulse width modulation, a pulse is generated based on the magnitude relationship between the amplitude of an AC waveform as a voltage command and the amplitude of a triangular (including sawtooth) carrier (CA) waveform (see FIG. 7, etc.). . In some cases, the PWM waveform is directly generated by digital calculation without comparison with the carrier, but even in that case, there is a correlation between the amplitude of the AC waveform as the command value and the amplitude of the virtual carrier waveform.

In pulse width modulation by digital computation, the carrier is determined according to the control cycle of the rotary electric machine control device 1, such as the computation cycle of a microcomputer or the operation cycle of an electronic circuit. In other words, even when multi-phase AC power is used to drive the AC rotary electric machine 80, the carrier has a cycle (non-synchronized cycle) that is not constrained by the rotation speed or rotation angle (electrical angle) of the rotary electric machine 80. have. Therefore, neither the carrier nor each pulse generated based on the carrier are synchronized with the rotation of the rotating electric machine 80 . Therefore, modulation schemes such as sinusoidal pulse width modulation, space vector pulse width modulation, etc. are sometimes referred to as asynchronous modulation. On the other hand, a modulation method in which pulses are generated in synchronization with the rotation of the rotating electric machine 80 is called synchronous modulation. For example, in rectangular wave control (rectangular wave modulation), one pulse is output for one cycle of the electrical angle of the rotating electric machine 80, so the rectangular wave modulation is synchronous modulation.

By the way, as an index indicating the conversion rate from the DC voltage to the AC voltage, there is a modulation rate indicating the ratio of the effective value of the line-to-line voltage of the AC voltage of multiple phases to the DC voltage. Generally, the maximum modulation factor for sinusoidal pulse width modulation is about 0.61 (≈0.612), and the maximum modulation factor for space vector pulse width modulation control is about 0.71 (≈0.707). A modulation scheme having a modulation factor greater than about 0.71 is referred to as an "overmodulation pulse width modulation" as a modulation scheme having a higher than normal modulation factor. The maximum modulation factor for "overmodulation pulse width modulation" is about 0.78. This modulation rate of 0.78 is a physical (mathematical) limit value in power conversion from DC to AC. In overmodulation pulse width modulation, when the modulation rate reaches 0.78, it becomes rectangular wave modulation (one pulse modulation) in which one pulse is output in one cycle of the electrical angle. For square wave modulation, the modulation factor would be fixed at a physical limit of about 0.78.

Overmodulation pulse width modulation with a modulation factor of less than 0.78 can be realized using either the synchronous modulation method or the asynchronous modulation method. A typical modulation scheme for overmodulation pulse width modulation is discontinuous pulse width modulation. Discontinuous pulse width modulation can be realized using either the principle of synchronous modulation or asynchronous modulation. For example, when the synchronous modulation method is used, one pulse is output in one cycle of electrical angle in square wave modulation, but a plurality of pulses are output in one cycle of electrical angle in discontinuous pulse width modulation. If there are a plurality of pulses in one period of the electrical angle, the effective period of the pulses is reduced by that amount, so the modulation rate is lowered. Therefore, any modulation rate less than 0.78 can be realized by the synchronous modulation scheme, not limited to the modulation rate fixed at approximately 0.78. For example, multiple pulse modulation (Multi-Pulses) such as 9-pulse modulation (9-Pulses) that outputs 9 pulses and 5-Pulses (5-Pulses) that outputs 5 pulses in one cycle of the electrical angle is also possible. It is possible.

Further, the rotating electric machine control device 1 can execute shutdown control (SDN) and active short circuit control (ASC) as fail-safe control when an abnormality is detected in the inverter 10 or the rotating electric machine 80. Shutdown control is control to put the switching control signals to all the switching elements 3 constituting the inverter 10 in an inactive state so that the inverter 10 is turned off. Active short circuit control is a control in which either one of the upper switching elements 3H of the arms 3A of all of the multiple phases or the lower switching elements 3L of the arms 3A of all of the multiple phases is turned on, and the other is turned off. be. A case in which the upper switching elements 3H of the arms 3A of all the phases are turned on and the lower switching elements 3L of the arms 3A of all the phases are turned off is referred to as upper active short circuit control. A case in which the lower switching elements 3L of the arms 3A of all the phases are turned on and the upper switching elements 3H of the arms 3A of all the phases are turned off is referred to as lower active short circuit control.

When the inverters 10 are connected to both ends of the stator coil 8 as in the present embodiment, when one of the inverters 10 is short-circuited by active short circuit control, the multi-phase stator coils 8 in the one inverter 10 shorted. That is, the one inverter 10 becomes the neutral point, and the stator coil 8 is Y-connected. For this reason, the rotating electric machine control device 1 controls the open-winding rotating electric machine 80 via two inverters 10, and controls the rotating electric machine 80 via one inverter 10 (the inverter 10 not subjected to active short circuit control). It is possible to realize a form of controlling the rotary electric machine 80 of Y-connection. Therefore, in the present embodiment, not only fail-safe control but also active short-circuit control is included as a control form that can be selected in normal control. That is, the rotary electric machine control device 1 can further execute active short circuit control as a control method for the first inverter 11 and the second inverter 12 .

By the way, when one inverter 10 is subjected to vector control, eight space vectors can be defined according to the state of the three-phase arm 3A. Specifically, eight space vectors can be defined by a combination of three phases of two types of signal levels of the switching control signal of the upper switching element 3H (2 ³ =8). The signal levels of the three-phase switching control signals for the lower switching element 3L are complementary to the signal levels of the switching control signals for the upper switching element 3H. Therefore, the space vector can be defined by the signal level of the switching control signal on either the upper side or the lower side.

When the signal level of each switching control signal is "1" when it is high level and "0" when it is low level, and the signal level of the switching control signals of the U-phase, V-phase, and W-phase is indicated by (UVW), The eight space vectors are (000), (001), (010), (011), (100), (101), (110), and (111). Of the eight space vectors, (000) and (111) are called zero vectors or null vectors because the line-to-line voltage is zero and no voltage is applied to the rotating electrical machine 80, and the dq axis vector coordinate system shows the same coordinates in . On the other hand, the other six space vectors are called active vectors and show different coordinates in the dq-axis vector coordinate system.

As shown in FIG. 1, when the two inverters 10 are vector-controlled, 64 space vectors can be defined by the signal level of either the upper-stage or lower-stage switching control signal (2 ^{( 3.2)} = 2 ⁶ = 64). Of these, 10 are null vectors. Signal levels of U-phase (U1-phase), V-phase (V1-phase) and W-phase (W1-phase) of first inverter 11 and U-phase (U2-phase), V-phase (V2-phase) and W-phase of second inverter 12 When the signal level of (W2 phase) is expressed by (U1V1W1-U2V2W2), (000-000), (001-001), (010-010), (011-011), (100-100), (101 −101), (110-110), (111-111), (000-111), and (111-000) are null vectors with zero line voltage. The remaining 54 are active vectors with valid magnitudes from the origin (coordinates of the null vector) to 18 different coordinates in the dq-axis vector coordinate system.

The coordinates of the null vector and the coordinates of the 18 active vectors are plotted in FIG. Z0 indicates the coordinates of the null vector in the dq-axis vector coordinate system (10 vectors have the same coordinates). Z1 to Z6 indicate coordinates of active vectors substantially realized by one inverter 10 in the dq-axis vector coordinate system. Z7 to Z18 indicate coordinates corresponding to active vectors realized by two inverters 10 in the dq-axis vector coordinate system.

Z1 is (000-011), (100-000), (100-111), (111-011), Z2 is (000-001), (110-000), (110-111), (111-001 ), Z3 is (000-101), (010-000), (010-111), (111-101), Z4 is (000-100), (011-000), (011-111), (111 -100), Z5 is (000-110), (001-000), (001-111), (111-110), Z6 is (000-010), (101-000), (101-111), Contains (111-010). These 24 space vectors are combinations in which the space vector of one inverter 10 is the null vector and the space vector of the other inverter 10 is the active vector.

Incidentally, Z1: (101-001), (110-010), Z2: (010-011), (100-101), Z3: (011-001), (110-100), Z4: (001-101 ), (010-110), Z5: (011-010), (101-100), and Z6: (001-011), (100-110), the coordinates of Z1 to Z6 are also show. However, it is a combination in which one inverter 10 is not a null vector and two inverters 10 are both active vectors.

Z7 is (100-001), (110-011), Z8 is (010-001), (110-101), Z9 is (010-100), (011-101), Z10 is (001-100), (011-110), Z11 corresponds to (001-010), (101-110), and Z12 corresponds to (100-010), (101-011) 12 space vectors. Also, Z13 is (100-011), Z14 is (110-001), Z15 is (010-101), Z16 is (011-100), Z17 is (001-110), Z18 is (101-010) It corresponds to 6 space vectors.

FIG. 4 illustrates a vector diagram at one operating point in the dq-axis vector coordinate system of rotating electric machine 80 . In the figure, "V1" indicates a first voltage vector indicating the voltage by the first inverter 11, and "V2" indicates a second voltage vector indicating the voltage by the second inverter 12. FIG. The voltage appearing in the open winding stator coil 8 through the two inverters 10 corresponds to the difference "V1-V2" between the first voltage vector V1 and the second voltage vector V2. "Va" in the figure indicates a composite voltage vector appearing in the stator coil 8. FIG. Also, "Ia" indicates the current flowing through the stator coil 8 of the rotary electric machine 80 . As shown in FIG. 4, when the first inverter 11 and the second inverter 12 are controlled such that the directions of the first voltage vector V1 and the second voltage vector V2 differ by 180 degrees, the composite voltage vector Va is , the magnitude of the second voltage vector V2 is added to the direction of the first voltage vector V1.

When the rotary electric machine 80 having open windings of a plurality of phases independent of each other is driven and controlled via the two inverters 10 as in the present embodiment, the two inverters 10 are generally controlled by the same control method. Switching controlled. However, the switching control method is determined according to various factors (operating conditions) such as the torque required for the rotating electric machine 80, the rotation speed, and the voltage on the DC side, so that operation with higher system efficiency is possible. preferably. Therefore, the rotating electric machine control device 1 has control modes in which the first inverter 11 and the second inverter 12 are controlled by different control methods according to the operating region (control region R) of the rotating electric machine 80 . According to experiments and simulations by the inventors, system efficiency can be increased by having a control mode in which the first inverter 11 and the second inverter 12 are controlled by different control methods according to the operating conditions of the rotating electric machine 80. confirmed that it can be done.

In this embodiment, the rotary electric machine control device 1 controls one inverter 10 (here, the first inverter 11) of the first inverter 11 and the second inverter 12 by rectangular wave control, and controls the other inverter 10 (here, the second inverter 11). 2 inverter 12) is controlled by special pulse width modulation control (SP-PWM), which is one of the pulse width modulation controls. Here, the special pulse width modulation control is a control method that provides a switching pattern based on the difference between a switching pattern by pulse width modulation control when generating a target voltage in the stator coil 8 and a switching pattern by rectangular wave control. be. Details will be described later with reference to FIGS. 8 to 19 and the like.

As described above, in the present embodiment, the second switching element 32 that constitutes the second inverter 12 is more likely than the first switching element 31 that constitutes the first inverter 11 to transition between the off state and the on state. is a switching element with a relatively small switching loss. When the first inverter 11 is controlled by square wave control, the number of times of switching is reduced compared to the second inverter 12 controlled by special pulse width modulation control. In other words, the loss of the entire system can be suppressed in the high-speed region VRH where high output is required by allowing the second inverter 12 with relatively small switching loss to perform more switching.

Of course, there are control modes other than the mode in which object control is executed. Each control mode is set corresponding to a control region R (see FIG. 5, etc.) of the rotating electric machine 80 . As shown in FIG. 5, in the present embodiment, as the control region R of the rotating electric machine 80, there are a low speed region VRL and a high speed region VRH in which the rotational speed of the rotating electric machine 80 at the same torque T is higher than that of the low speed region VRL. is set. Target control is executed in the high speed range VRH.

Further, as shown in FIG. 5, the high-speed region VRH is divided into the high-speed region VRH. A second high speed region VRH2 higher than VRH1 can be set. The target control executed in the high speed range VRH is of two types: a first target control executed in the first high speed range VRH1 and a second target control executed in the second high speed range VRH2. can have Incidentally, when the high speed range VRH is not divided, it is preferable that the target control executed in the entire region of the high speed range VRH is the first target control.

As described above, the pulse width modulation control includes, as control methods, continuous pulse width modulation control (CPWM) in which pulse width modulation is performed continuously for all of the multi-phase arms 3A, and discontinuous pulse width modulation control (DPWM) that performs pulse width modulation including a period in which the switching element 3 is fixed in an ON state or an OFF state. In addition, as described above, the special pulse width modulation control (SP-PWM) is based on the difference between the switching pattern by pulse width modulation control when generating the target voltage in the stator coil 8 and the switching pattern by rectangular wave control. This is a control method with a switching pattern that Continuous pulse width modulation is used as the pulse width modulation control in the first object control, and discontinuous pulse width modulation is used as the pulse width modulation control in the second object control.

That is, in the first high-speed range VRH1, the rotating electric machine control device 1 controls one of the first inverter 11 and the second inverter 12, the inverter 10 (here, the first inverter 11), by rectangular wave control as target control. , the other inverter 10 (here, the second inverter 12) is controlled by special continuous pulse width modulation control (SP-CPWM), which is special pulse width modulation control (SP-PWM) based on continuous pulse width modulation control (CPWM). Execute the first object control. Further, in the second high-speed region VRH2, the rotating electric machine control device 1 controls one of the first inverter 11 and the second inverter 12, the inverter 10 (here, the first inverter 11), by rectangular wave control as target control. , the other inverter 10 (here, the second inverter 12) is controlled by special discontinuous pulse width modulation (SP-DPWM), which is special pulse width modulation control (SP-PWM) based on discontinuous pulse width modulation (DPWM) 2nd object control to do is performed.

The maximum modulation rate with discontinuous pulse width modulation control is greater than the maximum modulation rate with continuous pulse width modulation control. The second high-speed region VRH2 is a control region R in which the rotation speed of the rotating electric machine 80 is higher than that of the first high-speed region VRH1 at the same torque T. It is preferable to modulate with a higher modulation rate than the speed range VRH1. By executing special continuous pulse width modulation control based on continuous pulse width modulation in the first high speed range VRH1 and special continuous pulse width modulation control based on discontinuous pulse width modulation in the second high speed range VRH2, The rotary electric machine 80 can be appropriately driven over the entire speed range VRH.

Further, as shown in FIG. 6, it is preferable that a super-high speed region VRSH in which the rotation speed of the rotary electric machine at the same torque T is higher than that of the high speed region VRH is further set as the control region R. In this ultra-high speed region VRSH, both inverters 10 of the first inverter 11 and the second inverter 12 are controlled by rectangular wave control. In the high-speed range VRH, where the rotational speed of the rotating electrical machine at the same torque T is lower than the ultra-high-speed range VRSH, one inverter 10 is controlled by rectangular wave control, and the other inverter 10 is controlled by special discontinuous pulse width modulation. ing. The maximum modulation factor for normal discontinuous pulse width modulation is approximately 0.78 for square wave control. Since the maximum modulation rate of the special discontinuous pulse width modulation based on discontinuous pulse width modulation is also approximately 0.78, it is possible to appropriately drive the rotating electric machine 80 over the high speed region VRH and the super high speed region VRSH. can be done.

In the low speed range VRL, one inverter 10 (here, the first inverter 11) of the first inverter 11 and the second inverter 12 is controlled by active short circuit control, and the other inverter 10 (here, the second inverter 12) is controlled by active short circuit control. ) is executed by pulse width modulation control. That is, substantially only one of the two inverters 10 (for example, the second inverter 12) drives the rotating electric machine 80 . Since one inverter 10 does not perform a switching operation, the switching loss can be reduced by that amount, and as a result, the rotary electric machine 80 can be driven while suppressing the loss of the entire system.

As described above, in the present embodiment, the second inverter 12 is configured using switching elements with relatively small switching loss compared to the first inverter 11 . When the first inverter 11 is subjected to active short-circuit control, the switching loss of the first inverter 11, which has a relatively large switching loss, becomes almost zero. In addition, since the switching loss of the second inverter 12 that switches is relatively small, the loss of the entire system can be suppressed in the low speed range VRL.

Further, as shown in FIG. 7, the low speed region VRL is also divided, and within the low speed region VRL, the rotation speed of the rotating electric machine 80 at the same torque T as that of the first low speed region VRL1 is higher than that of the first low speed region. A high second low speed range VRL2 can be set. The target low-speed control executed in the low speed range VRL includes the first target low-speed control executed in the first low-speed range VRL1 and the second target low-speed control executed in the second low-speed range VRL2. You can have two types of control: If the low speed range VRL is not divided, it is preferable that the target control executed in the entire low speed range VRL is the first target low speed control.

The pulse width modulation control includes, as a control method, continuous pulse width modulation control for continuously performing pulse width modulation on all of the multi-phase arms 3A, and switching the switching elements 3 on or off for some of the multi-phase arms 3A. and a discontinuous pulse width modulation control that provides pulse width modulation with a fixed off period. Continuous pulse width modulation control is used in the first low speed range VRL1, and discontinuous pulse width modulation control is used in the second low speed range VRL2.

Specifically, in the first low speed range VRL1, the rotating electric machine control device 1 controls one of the first inverter 11 and the second inverter 12 (here, the first inverter 11) as the target low speed range control. A first target low speed range control is executed in which control is performed by active short circuit control and the other inverter 10 (here, the second inverter 12) is controlled by continuous pulse width modulation control. Further, in the second low-speed range VRK2, the rotating electric machine control device 1 activates one inverter 10 (here, the first inverter 11) of the first inverter 11 and the second inverter 12 as target low-speed range control. control, and the other inverter 10 (here, the second inverter 12) is controlled by discontinuous pulse width modulation control.

The maximum modulation rate with discontinuous pulse width modulation control is greater than the maximum modulation rate with continuous pulse width modulation control. The second low speed range VRL2 is a control range R in which the rotational speed of the rotating electric machine 80 is higher than that of the first low speed range VRL1 at the same torque T. It is preferable to modulate with a higher modulation rate than the speed range VRL1. A first target low speed range control using continuous pulse width modulation control is executed in the first low speed range VRL1, and a second target low speed range control using discontinuous pulse width modulation is executed in the second low speed range VRL2. As a result, the rotating electric machine 80 can be appropriately driven over the entire low speed range VRL.

Note that, during modulation in the low speed range VRL, noise in the audible band may occur depending on the frequency of the carrier CA (see FIGS. 31, 32, etc.). In the low speed range VRL, the noise accompanying the running of the vehicle (running noise such as the contact sound between the tires and the road surface) is also small, so if the noise output from the inverter 10 is in the audible frequency band, the noise is used. may be easier for people to hear. Here, by increasing the frequency of the carrier CA, the frequency of the noise may be made out of the audible band. Since the second inverter 12 is configured using a switching element with relatively small switching loss compared to the first inverter 11, an increase in switching loss is suppressed even if the frequency of the carrier CA is increased.

By the way, as illustrated in FIGS. 36 and 37, the first inverter 11 and the second inverter 12 may be configured using the same switching element 3 . Further, even when the second inverter 12 is configured using a switching element having a relatively small switching loss compared to the first inverter 11 as illustrated in FIG. The frequencies of the 12 carriers CA may not be set high. In such a case, the first inverter 11 is not limited to being controlled by active short-circuit control, and the second inverter 12 may be controlled by active short-circuit control.

In such a case, the first inverter 11 is operated in the low speed range VRL so that only the inverter 10 (here, the second inverter 12) that is not subjected to active short-circuit control is worn out due to frequent switching. It is preferable to alternately switch the control method for controlling and the control method for controlling the second inverter 12 according to a predetermined condition. By switching the control method, it is possible to suppress an increase in the discharge amount of only one of the first DC power supply 61 and the second DC power supply 62 . Here, it is preferable that the prescribed condition is, for example, a certain period of time or the discharge amount of the DC power supply 6 .

Further, as shown in FIG. 7, an intermediate speed range VRM in which the rotation speed of the rotary electric machine 80 at the same torque T is higher than the low speed range VRL and lower than the high speed range VRH can be further set as the control range R, as shown in FIG. . In the intermediate speed range VRM, both the first inverter 11 and the second inverter 12 are controlled by discontinuous pulse width modulation control.

As described above, the first low speed region VRL1, the second low speed region VRL2, the intermediate speed region VRM, the first high speed region VRH1, the second high speed region VRH2, and the super high speed region VRSH are set as the control region R. Also, an example of a control method applied to the first inverter 11 and the second inverter 12 is shown in Table 1 below.

Here, the boundaries of each control region R are the rotational speed of the rotating electrical machine 80 corresponding to the torque of the rotating electrical machine 80 and the effective value of the line voltage of the multi-phase AC voltage with respect to the DC voltage (even if it is a command value, the output It is preferable that it is set in accordance with at least one of the ratio of the voltage and the ratio of the conversion value from the voltage.

The operating conditions of the rotating electric machine 80 are often defined by the relationship between the rotational speed and the torque, as illustrated in FIGS. 5-7. Preferably, the control region R is set based on one parameter, the rotational speed. Here, it is possible to set the rotational speed that defines the boundary of the control region R to be constant regardless of the torque, but the rotational speed that defines the boundary of the control region R has different values depending on the torque. It is more preferable to set as follows. By doing so, it is possible to drive and control the rotating electrical machine 80 with high efficiency according to the operating conditions of the rotating electrical machine 80 .

Further, for example, when a high output (high rotational speed or high torque) is required for the rotating electrical machine 80, the voltage-type inverter increases the DC voltage or converts the DC voltage into the AC voltage. By doing so, the request is realized. If the DC voltage is constant, this requirement can be met by increasing the rate at which the DC voltage is converted to AC voltage. This ratio can be expressed as the ratio of the effective value of the three-phase AC power to the DC power (in the case of a voltage-type inverter, it is equivalent to the ratio of the effective value of the line voltage of the three-phase AC voltage to the DC voltage). . As described above, there are various control methods for controlling the inverter 10, ranging from low to high ratios.

If the control region is set based on the ratio (modulation factor) of the effective value of the line voltage of the three-phase AC voltage to the DC voltage, which is determined according to the requirements of the rotating electrical machine 80, the operating conditions of the rotating electrical machine 80 Therefore, the rotary electric machine 80 can be driven and controlled with high efficiency. Table 2 shown below corresponds to Table 1 above and illustrates the modulation factor corresponding to each control region R. Although the details will be described later, in the table, "Mi_inv1" indicates the modulation rate of the first inverter 11, "Mi_inv2" indicates the modulation rate of the second inverter 12, and "Mi_sys" indicates the modulation rate of the entire system.

In this embodiment, the inter-terminal voltage "E1" of the first DC power supply 61 and the inter-terminal voltage "E2" of the second DC power supply 62 are the same (both voltage "E"). Assuming that the effective value of the AC side of the first inverter 11 is "Va_inv1" and the effective value of the AC side of the second inverter 12 is "Va_inv2", the modulation factor "Mi_inv1" of the first inverter 11 and the modulation of the second inverter 12 are The ratio "Mi_inv2" is given by the following equations (1) and (2). Also, the modulation factor "Mi_sys" of the entire system is given by the following equation (3).

Mi_inv1=Va_inv1/E1=Va_inv1/E (1)
Mi_inv2=Va_inv2/E2=Va_inv2/E (2)
Mi_sys=(Va_inv1+Va_inv2)/(E1+E2)
=(Va_inv1+Va_inv2)/2E (3)

As for the instantaneous voltage value, it is necessary to consider the vector at the moment, but simply considering the modulation rate, from the equations (1) to (3), the modulation rate "Mi_sys" of the entire system is "(Mi_inv1 + Mi_inv2 )/2″. Table 2 shows the modulation factor corresponding to each control area R as a rated value. Therefore, in actual control, in consideration of hunting or the like when the control method changes in the control regions R, the modulation factors corresponding to the respective control regions R may include overlapping ranges.

The modulation factor "X" is set based on the theoretical upper limit value (approximately 0.707) of the modulation factor by continuous pulse width modulation (space vector pulse width modulation), and in consideration of dead time. As shown in Table 2, in the low speed range VRL (first low speed range VRL1 and second low speed range VRL2), only one inverter 10 may perform modulation. Continuous pulse width modulation control may be executed over the entire low speed range VRL. Based on the theoretical upper limit of the modulation rate by pulse width modulation control (approximately 0.707 in space vector pulse width modulation), and considering the dead time, it is set to, for example, about 0.5 to 0.6. . Therefore, the modulation factor "X" is set to a value of about 0.25 to 0.3, for example. The modulation factors "a, b, c" are appropriately set based on experiments, simulations, or the like.

The control method in each control region R will be described below with reference to waveform examples of the U-phase voltage commands (Vu1 ^** , Vu2 ^** ) and the U-phase upper switching control signals (Su1+, Su2+). Illustrations of the second U-phase lower-stage switching control signal Su2- and the V-phase and W-phase are omitted.

First, the special pulse width modulation control (SP-PWM), which is executed in the high speed range VRH and is the most characteristic of this embodiment, will be described with reference to FIGS. 8 to 19. FIG. FIG. 8 shows special continuous pulse width modulation control (SP-CPWM) and FIG. 9 shows special discontinuous pulse width modulation control (SP-DPWM).

8 and 9 show a carrier CA common to the first inverter 11 and the second inverter 12, a first U-phase voltage command Vu1 ^** which is a voltage command for the first inverter 11, and a voltage command for the second inverter 12. An example of the second U-phase voltage command Vu2 ^** , the first U-phase upper switching control signal Su1+, and the second U-phase upper switching control signal Su2+ is shown. The first U-phase lower-stage switching control signal Su1-, the second U-phase lower-stage switching control signal Su2-, and the V-phase and W-phase are not shown (the same applies to other control methods).

For example, the carrier CA varies between "0<CA<1", and the voltage command (V ^** ) basically varies within the range of " ^0≤V** ≤1". By comparing the carrier CA with the voltage command (V ^** ), the switching control signal becomes "1" when the voltage command is greater than or equal to the carrier CA, and the switching control signal becomes "0" when the voltage command is less than the carrier CA. becomes. The comparison logic between carrier CA and voltage command (V ^** ) is the same in the following description.

As described above, the special pulse width modulation control (SP-PWM) is switching based on the difference between the switching pattern by pulse width modulation control when generating a target voltage in the stator coil 8 and the switching pattern by rectangular wave control. It is a control method that becomes a pattern. Therefore, the voltage command (V ** ) for the special pulse width modulation control (SP-PWM) is the voltage command (V ^** ) for the pulse width modulation control when generating the target voltage in the stator coil 8 and the rectangular voltage command (V ^** ). It is set based on the difference from the voltage command (V ^** ) for wave control. For example, the voltage command (V ^** ) for special continuous pulse width modulation control (SP-CPWM) is the voltage command (V ^** ) for continuous pulse width modulation control when the target voltage is generated in the stator coil 8. , is set based on the difference from the voltage command (V ^** ) for rectangular wave control. The voltage command (V ^** ) for special discontinuous pulse width modulation control (SP-DPWM) is the voltage command (V ^** ) for discontinuous pulse width modulation control when the target voltage is generated in the stator coil 8 ) and the voltage command (V ^** ) for rectangular wave control.

The principle and procedure for calculating the voltage command (V ^** ) for the special pulse width modulation control will be described below with reference to the block diagram of FIG. 2 and FIGS. 10 to 19. FIG. 10 to 13 show the principle of calculating the voltage command (V ^** ) for special continuous pulse width modulation control, and FIGS. 14 to 17 show the voltage command (V ^** ) for special discontinuous pulse width modulation control. , and FIGS. 18 and 19 show the procedure for calculating the voltage command (V ^** ) for special pulse width modulation control. Here, the U-phase voltage command (Vu ^** ) of the three-phase voltage commands (V ^** ) will be described as a representative example.

FIG. 10 shows a voltage command (Vu2 ^** ) for special continuous pulse width modulation control, a voltage command (Vu1 ^** ) for square wave control, and a carrier CA as illustrated in FIG. That is, it shows the calculation result of the voltage command (Vu2 ^** ) for the special continuous pulse width modulation control. As described above, the carrier CA changes between "0<CA<1", and the voltage commands (Vu1 ^** , Vu2 ^** ) change between "0" and "1".

FIG. 11 shows a voltage command (Vu2 ^** ) for continuous pulse width modulation control, a voltage command (Vu1 ^** ) for rectangular wave control, and a carrier CA. For example, as shown in FIG. 2, the three-phase voltage command calculation unit 73B for special modulation of the second voltage control unit 72 that calculates the three-phase voltage command for the second inverter 12 calculates the three-phase voltage command for the first inverter 11 ( Vu1 ^** ) and the voltage command for the second inverter 12 (Vu2 ^** ). Here, as the three-phase voltage command (Vu1 ^** ) for the first inverter 11, the voltage command for rectangular wave control (1-Pulse) is calculated, and as the three-phase voltage command (Vu2 ^** ) for the second inverter 12, The voltage command for continuous pulse width modulation (CPWM) is calculated. As shown in the first step #1 of FIG. 18, these voltage commands are acquired as basic voltage commands (basic voltage command acquisition step). “Vu_INV1_Ref” is a basic voltage command (first basic voltage command) for the first inverter 11 . “Vu_INV2_Ref” is a basic voltage command (second basic voltage command) for the second inverter 12 . The first basic voltage command corresponds to a rectangular wave voltage command, and the second basic voltage command corresponds to a pulse width modulation voltage command (here, a continuous pulse width modulation voltage command).

FIG. 12 shows voltage commands after the second step #2 and the third step #3 of FIG. 18 are executed. In the second step #2, a total voltage command "Vu_total_Ref" (system voltage command) output using the first inverter 11 and the second inverter 12 is calculated (system voltage command calculation step). As described above with reference to FIG. 4 and the like, the voltage command for the first inverter 11 and the voltage command for the second inverter 12 are set to be 180 degrees out of phase. Therefore, as shown in FIGS. 12 and 18, the system voltage command "Vu_total_Ref" is calculated as the difference between the first basic voltage command "Vu_INV1_Ref" and the second basic voltage command "Vu_INV2_Ref".

As shown in FIG. 12, the wave height of the system voltage command "Vu_total_Ref" becomes larger than the range of carrier CA "0<CA<1", and its amplitude center is "0". In order to match the amplitude center of the system voltage command "Vu_total_Ref" and the amplitude center of the first basic voltage command "Vu_INV1_Ref", in the third step #3, the amplitude center of the first basic voltage command "Vu_INV1_Ref" is set to the carrier CA. is shifted from "0.5", which is the center of the domain "0<CA<1", to "0". The third step #3 can be called a negative shift step in a narrow sense, but since it is a correction associated with the calculation of the system voltage command, it may be included in the system voltage command calculation step. In this embodiment, the second step #2 and the third step #3 correspond to the system voltage command calculation step. In addition, in the block diagram of FIG. 2 (three-phase voltage command calculation section 73B for special modulation), the difference calculation in the second step #2 is illustrated as a representative for simplification.

FIG. 13 shows voltage commands after the fourth step #4 of FIG. 18 is executed. In the fourth step #4, the second basic voltage command is calculated based on the first basic voltage command "Vu_INV1_Ref" and the system voltage command "Vu_total_Ref" calculated in the system voltage command calculation steps (#2, #3). "Vu_INV2_Ref" is optimized for special continuous pulse width modulation (voltage command optimization step). As shown in FIGS. 13 and 18, the second basic voltage command "Vu_INV2_Ref" is calculated as the difference between the first basic voltage command "Vu_INV1_Ref" and the system voltage command "Vu_total_Ref". The second basic voltage command "Vu_INV2_Ref" corresponds to the special pulse width modulation voltage command (here, the special discontinuous pulse width modulation voltage command) (finally, the fifth step #5 and sixth step It becomes a voltage command for special pulse width modulation via #6.).

The center of amplitude of the first basic voltage command "Vu_INV1_Ref" and the second basic voltage command "Vu_INV2_Ref" is "0" as shown in FIG. 13 at the completion of execution of the fourth step #4. Therefore, in the fifth step #5, plus shift processing is executed to return the amplitude center from "0" to "0.5", which is the center of the carrier CA's domain "0<CA<1" (plus shift step). In the subsequent sixth step #6, the voltage command "Vu1 ^** " for the first inverter 11 is set to the first basic voltage command "Vu_INV1_Ref", and the voltage command "Vu2 ^** " for the second inverter 12 is set to the second basic voltage. The command "Vu_INV2_Ref" is set (voltage command setting step). Similar to the third step #3 (minus shift step), the fifth step #5 is a correction operation. Therefore, just as the third step #3 is included in the system voltage command calculation step together with the second step #2, the fifth step #5 may be included in the voltage command setting step together with the sixth step #6. In this embodiment, the fifth step #5 and the sixth step #6 correspond to the voltage command setting step.

Although the block diagram of FIG. 2 is simplified, the special modulation three-phase voltage command calculation section 73B executes the first step #1 to the sixth step #6. The modulation unit 75 for special modulation generates a switching control signal for special pulse width modulation control (SP-PWM) based on the voltage command (V ^** ) for special pulse width modulation control (SP-PWM). When special pulse width modulation control (SP-PWM) is selected as the control method, a switching control signal for special pulse width modulation control (SP-PWM) is output via the selector 76 . FIG. 2 shows a three-phase voltage command calculation unit 73 and a modulation unit 74 for normal modulation, a special modulation three-phase voltage command calculation unit 73B and a special modulation modulation unit 75 for special pulse width modulation, A form including a selection unit 76 that selects and outputs the switching control signal generated by each modulation unit (74, 75) is illustrated. However, as described above, the three-phase voltage command for normal modulation and the three-phase voltage command for special modulation generated by the modulation unit for special modulation 75 are selected by the selection unit, and based on the selected voltage command, common may generate the switching control signal.

FIG. 14 shows a voltage command (Vu2 ^** ) for special discontinuous pulse width modulation control, a voltage command (Vu1 ^** ) for square wave control, and a carrier CA as illustrated in FIG. That is, it shows the calculation result of the voltage command (Vu2 ^** ) for the special discontinuous pulse width modulation control. The voltage command (Vu1 ^** ) for rectangular wave control changes in the range of "0" or more and "1" or less in response to the carrier CA which changes between "0 and 1", but is particularly discontinuous. The voltage command (Vu2 ^** ) of the pulse width modulation control changes including the range of "0" or less and "1" or more, which is outside the range of the carrier CA.

FIG. 15 shows a voltage command (Vu2 ^** ) for discontinuous pulse width modulation control, a voltage command (Vu1 ^** ) for rectangular wave control, and a carrier CA. As described above, the three-phase voltage command calculation unit 73B for special modulation (see FIG. 2) calculates the three-phase voltage command (Vu1 ^** ) for the first inverter 11 and the voltage command (Vu2 ^** ) for the second inverter 12. and both. Here, as the three-phase voltage command (Vu1 ^** ) for the first inverter 11, the voltage command for rectangular wave control (1-Pulse) is calculated, and as the three-phase voltage command (Vu2 ^** ) for the second inverter 12, A voltage command for discontinuous pulse width modulation (DPWM) is calculated. As described above with reference to FIG. 18, in the first step #1, the first basic voltage command "Vu_INV1_Ref" and the second basic voltage command "Vu_INV2_Ref" are obtained (basic voltage command obtaining step). The first basic voltage command corresponds to a rectangular wave voltage command, and the second basic voltage command corresponds to a pulse width modulation voltage command (here, a discontinuous pulse width modulation voltage command).

FIG. 16 shows voltage commands after the second step #2 and the third step #3 of FIG. 18 are executed. In the second step #2, a total voltage command “Vu_total_Ref” (system voltage command) output using the first inverter 11 and the second inverter 12 is calculated. As shown in FIGS. 16 and 18, the system voltage command "Vu_total_Ref" is calculated as the difference between the first basic voltage command "Vu_INV1_Ref" and the second basic voltage command "Vu_INV2_Ref".

As shown in FIG. 16, the wave height of the system voltage command "Vu_total_Ref" becomes larger than the range of carrier CA "0<CA<1", and its amplitude center is "0". In order to match the amplitude center of the system voltage command "Vu_total_Ref" and the amplitude center of the first basic voltage command "Vu_INV1_Ref", in the third step #3, the amplitude center of the first basic voltage command "Vu_INV1_Ref" is set to the carrier CA. is shifted from "0.5", which is the center of the amplitude, to "0" (minus shift step). As described above, the third step #3 is a correction associated with the calculation of the system voltage command, so it may be included in the system voltage command calculation step. In this embodiment, the second step #2 and the third step #3 correspond to the system voltage command calculation step.

FIG. 17 shows voltage commands after the fourth step #4 of FIG. 18 is executed. In the fourth step #4, the second basic voltage command is calculated based on the first basic voltage command "Vu_INV1_Ref" and the system voltage command "Vu_total_Ref" calculated in the system voltage command calculation steps (#2, #3). "Vu_INV2_Ref" is optimized for special continuous pulse width modulation (voltage command optimization step). As shown in FIGS. 17 and 18, the second basic voltage command "Vu_INV2_Ref" is calculated as the difference between the first basic voltage command "Vu_INV1_Ref" and the system voltage command "Vu_total_Ref". The second basic voltage command "Vu_INV2_Ref" corresponds to the special pulse width modulation voltage command (here, the special discontinuous pulse width modulation voltage command) (finally, the fifth step #5 and sixth step It becomes a voltage command for special pulse width modulation via #6.).

The center of amplitude of the first basic voltage command "Vu_INV1_Ref" and the second basic voltage command "Vu_INV2_Ref" is "0" as shown in FIG. 17 at the completion of execution of the fourth step #4. Therefore, in the fifth step #5, plus shift processing is executed to return the amplitude center from "0" to "0.5", which is the amplitude center of the carrier CA (plus shift step). In the subsequent sixth step #6, the voltage command "Vu1 ^** " for the first inverter 11 is set to the first basic voltage command "Vu_INV1_Ref", and the voltage command "Vu2 ^** " for the second inverter 12 is set to the second basic voltage. The command "Vu_INV2_Ref" is set (voltage command setting step). Like the third step #3 (negative shift step), the fifth step #5 is a correction calculation, so the fifth step #5 also sets the voltage command together with the sixth step #6, similarly to the system voltage command calculation step. may be included in the step. In this embodiment, the fifth step #5 and the sixth step #6 correspond to the voltage command setting step. As described above, the special modulation three-phase voltage command calculator 73B executes the first step #1 to the sixth step #6.

The flowchart of FIG. 19 exemplifies a mode in which the seventh step #7 is further performed. The modulation section 75 for special modulation executes the seventh step #7. The three-phase voltage command for normal modulation and the three-phase voltage command for special modulation generated by the modulation unit 75 for special modulation are selected in the selection unit, and based on the selected voltage command, the common modulation unit When the switching control signal is generated, the seventh step #7 is executed in the common modulating section.

In the seventh step #7, the carrier frequency F _CA is set by multiplying the frequency "FCA" (carrier frequency) of the carrier _CA by "K" with "K" set to a coefficient greater than "1". That is, the carrier frequency _FCA is increased to increase the modulation resolution. "K" can be, for example, "2". This effect will be described later with reference to FIGS. 20 to 29 (especially FIGS. 26 to 29). Note that the carrier frequency _FCA corresponds to the modulation frequency.

As described above with reference to FIGS. 10 to 19, special pulse width modulation control can be said to be a control method in which a switching pattern is generated based on a voltage command for special pulse width modulation. Specifically, when a target voltage is generated in the stator coil 8 which is an open winding, a voltage command for generating a switching pattern of one inverter controlled by rectangular wave control is defined as a voltage command for rectangular wave. The voltage command for pulse width modulation is a voltage command that is 180 degrees out of phase with the voltage command for pulse width modulation, and the voltage command for generating the switching pattern of the other inverter controlled by pulse width modulation control when generating the target voltage is the voltage command for pulse width modulation. The difference between the voltage command for rectangular wave and the voltage command for pulse width modulation is set as the system voltage command, which is the voltage command for the entire two inverters, and the system voltage command and the voltage for rectangular wave are obtained in a state where the amplitude centers are aligned. The special pulse width modulation control can be said to be a control method in which a switching pattern is generated based on the special pulse width modulation voltage command, using the difference from the command as the special pulse width modulation voltage command.

Further, as described above with reference to FIG. 19, in the low speed region VRL, when at least one of the first inverter 11 and the second inverter 12 is controlled by pulse width modulation control, the high speed region VRH Then, special pulse width modulation control may be performed with a modulation frequency higher than the modulation frequency in the pulse width modulation control.

As described above with reference to Tables 1, 2, etc., the special pulse width modulation control is performed in the high speed range VRH. In the high speed region VRH, the first inverter 11 is driven by square wave control and the second inverter 12 is driven by special pulse width modulation control. Below, in a state where the first inverter 11 is driven by rectangular wave control, the second inverter 12 is driven by special pulse width modulation control, compared with the case where the second inverter 12 is driven by normal pulse width modulation control. Advantages when driven will be described. Furthermore, the advantage of increasing the carrier frequency _FCA (increasing the modulation frequency) as described above with reference to FIG. 19 will also be described.

The waveform diagrams of FIGS. 20 to 29 are also referred to in the following description. 20 to 29 show the results of speed sweep experiments and speed sweep simulations in which the rotation speed of the rotary electric machine 80 was increased over time.

The waveform diagrams of FIGS. 20 and 21 show the dq-axis currents (Id, Iq) when rectangular wave control (1-Pulse) and normal continuous pulse width modulation control (CPWM) are combined in the first high-speed range VRH1. , and the actual modulation factor (Mi_sys) are shown together with the three-phase current. The waveform diagrams of FIGS. 22 and 23 are obtained by combining rectangular wave control (1-Pulse) and normal continuous pulse width modulation control (CPWM) in the first high-speed region VRH1, which is higher than in FIGS. dq-axis current (Id, Iq) and actual modulation factor when rectangular wave control (1-Pulse) and normal discontinuous pulse width modulation control (DPWM) are combined in the second high-speed region VRH2 (Mi_sys) is shown together with the three phase currents. That is, in FIGS. 22 and 23, the rotational speed of the rotating electrical machine 80 increases with the passage of time, the first high speed range VRH1 shifts to the second high speed range VRH2, and the control method of the inverter 10 switches. 26 to 29 also show the waveforms in the case of FIG. As shown in FIGS. 20 to 23, both the dq-axis currents (Id, Iq) and the actual modulation factor (Mi_sys) have a frequency "6f" that is six times the motor electrical frequency f (the electrical frequency of the rotating electric machine 80). ripple appears.

Here, in order to improve this "6f" ripple, the second inverter 12 is controlled by special continuous pulse width modulation control (SP-CPWM) in the first high speed range VRH1, and the second inverter 12 is controlled in the second high speed range VRH2. Inverter 12 is controlled by special discontinuous pulse width modulation control (SP-DPWM). 24 to 27 show waveform diagrams in this case.

The waveform diagrams in FIGS. 24 and 25 correspond to the waveform diagrams in FIGS. 20 and 21, and at the same torque and the same rotational speed as in FIGS. 20 and 21, the waveform diagrams in FIGS. While the case where control (CPMW) is executed is illustrated, FIGS. 24 and 25 illustrate the case where special continuous pulse width modulation control (SP-CPWM) is executed. Similarly, the waveform diagrams in FIGS. 26 and 27 correspond to the waveform diagrams in FIGS. 22 and 23, and at the same torque and the same rotation speed as in FIGS. 24 and 25 illustrate the case where the width modulation control (CPMW, DPWM) is executed, whereas the case where the special pulse width modulation control (SP-CPWM, SP-DPWM) is executed. exemplified.

Specifically, the waveform diagrams of FIGS. 24 and 25 show the dq axis when square wave control (1-Pulse) and special continuous pulse width modulation control (SP-CPWM) are combined in the first high speed region VRH1. Currents (Id, Iq) and actual modulation factors (Mi_sys) are shown together with three-phase currents. The waveform diagrams of FIGS. 26 and 27 combine rectangular wave control (1-Pulse) and special continuous pulse width modulation control (SP-CPWM) in the first high-speed region VRH1, which is higher than that of FIGS. dq-axis current (Id, Iq) and actual The modulation factor (Mi_sys) is shown together with the 3-phase current.

Comparing FIGS. 20 to 21 with FIGS. 24 to 25, both the dq-axis currents (Id, Iq) and the actual modulation factor (Mi_sys) are ripples of the frequency “6f”, which is six times the motor electric frequency f. is reduced and the ripple is improved. However, when comparing FIGS. 22 to 23 with FIGS. 26 to 27, both the dq-axis currents (Id, Iq) and the actual modulation factor (Mi_sys) have a frequency twice the motor electric frequency f. It can be seen that a "2f" ripple appears. That is, on the relatively low speed side in the high speed range VRH, the combination of the rectangular wave control and the special pulse width modulation control has achieved an improvement of reducing the "6f" ripple. On the relatively high speed side in the speed range VRH, a new problem arises in that even if the "6f" ripple is reduced, a "2f" ripple occurs.

As shown in FIGS. 10 and 14, this "2f" ripple is generated by special pulse width modulation in the phases of the electrical angles π (180 degrees) and 2π (360 degrees) (the phases of the inflection points of the voltage command). It is believed that this is caused by a sudden change in the control voltage command (V ^** ). That is, in phases with electrical angles of ^.pi . For this reason, even if the carrier frequency _FCA has sufficient resolution in the normal pulse width modulation control, the special pulse width modulation control does not have enough resolution, and the pulse of the switching control signal may not be generated properly. Therefore, as described above with reference to FIG. 19, the carrier frequency _FCA is increased to increase the modulation resolution. FIGS. 28 and 29 show waveform diagrams when the carrier frequency _FCA is doubled with respect to FIGS. 26 and 27. FIG.

The waveform diagrams in FIGS. 28 and 29 correspond to the waveform diagrams in FIGS. 26 and 27, and at the same torque and the same rotation speed as in FIGS. 28 and 29, the _carrier frequency F A case where special pulse width modulation control (SP-CPWM, SP-DPWM) modulated by _CA is executed is illustrated. Specifically, the waveform diagrams of FIGS. 28 and 29 are obtained by increasing the carrier frequency F _AC to twice that of FIGS. When (1-Pulse) and special continuous pulse width modulation control (SP-CPWM) are combined, and in the second high speed region VRH2, the carrier frequency F _AC is doubled in FIGS. When (1-Pulse) and special discontinuous pulse width modulation control (SP-DPWM) are combined, dq-axis currents (Id, Iq) and real modulation factors (Mi_sys) are shown together with three-phase currents.

Comparing FIGS. 26 to 27 with FIGS. 28 to 29, both the dq-axis currents (Id, Iq) and the actual modulation factor (Mi_sys) are ripples of frequency “2f” which is twice the motor electric frequency f. is reduced and the ripple is improved. That is, in the high speed range VRH, it is preferable to execute the special pulse width modulation control with a modulation frequency higher than that in the pulse width modulation control executed in the low speed range VRL.

In this embodiment, special pulse width modulation control is performed on the second inverter 12 . As described above, the second switching element 32 forming the second inverter 12 is an element with less switching loss than the first switching element 31 forming the first inverter 11 . Therefore, even if the carrier frequency _FCA is increased, an increase in switching loss can be suppressed. That is, if the switching element 3 having a smaller switching loss than the switching element 3 forming one of the two inverters 10 is used to form the other inverter 10, then the control method will be a special pulse width It becomes easy to apply modulation control, and it is easy to improve the efficiency of the entire system while suppressing an increase in switching loss.

Of course, when the carrier frequency _FCA for performing normal pulse width modulation control has a frequency high enough to appropriately perform special pulse width modulation control even at the phase inflection points of π and 2π. For example, there is no need to raise the carrier frequency _FCA again when performing special pulse width modulation control. Therefore, when applying the special pulse width modulation control, it is necessary that the switching element 3 constituting one inverter 10 has a smaller switching loss than the switching element 3 constituting the other inverter 10, as shown in FIG. no. As illustrated in FIGS. 36 and 37, both inverters 10 may be configured using switching elements 3 having the same physical properties.

The waveform diagram of FIG. 30 shows the first U-phase voltage command Vu1 ^** , the second U-phase voltage command Vu2 ^** , the carrier CA, the first U-phase upper-side switching control signal Su1+, and the second U-phase voltage command Vu1** in the ultra-high speed region VRSH. An example with the phase upper stage switching control signal Su2+ is shown. As described above, both the first inverter 11 and the second inverter 12 are controlled by rectangular wave control in the super high speed range VRSH. Although the carrier CA is unnecessary when the inverter 10 is controlled by the rectangular wave modulation control, the carrier CA is also illustrated for easy comparison with other control methods.

The waveform diagram of FIG. 31 shows a first U-phase voltage command Vu1** that is the U-phase voltage command for the first inverter 11 in the first low speed range VRL1, and a second U-phase voltage command Vu1 ^** that is the U-phase voltage command for the second inverter 12 in the first low speed range VRL1. An example of the command Vu2 ^** , the carrier CA, the first U-phase upper switching control signal Su1+, and the second U-phase upper switching control signal Su2+ is shown. In the first low speed range VRL1, the second inverter 12 is controlled by continuous pulse width modulation control. As shown in FIG. 31, a pulsed second U-phase upper stage switching control signal Su2+ is generated based on the carrier CA and the second U-phase voltage command Vu2 ^** .

Since the first inverter 11 is controlled by active short circuit control, the first U-phase voltage command Vu1 ^** is fixed at, for example, "0", and the first U-phase upper-side switching control signal Su1+ is always at "0". Become. Although not shown, the first U-phase lower-stage switching control signal Su1- is always "1". As a result, the upper switching element 3H (31H) of the U-phase arm 3A of the first inverter 11 is turned off, and the lower switching element 3L (31L) is turned on. The same applies to the V-phase and W-phase, whereby the first inverter 11 is controlled by the lower active short circuit control. The first U-phase switching control signal Su1 may be set to a fixed value without setting the first U-phase voltage command Vu1 ^** .

The waveform diagram of FIG. 32 shows the first U-phase voltage command Vu1 ^** , the second U-phase voltage command Vu2 ^** , the carrier CA, the first U-phase upper-side switching control signal Su1+, and the second U-phase voltage command Vu2** in the second low-speed region VRL2. An example with the 2U-phase upper-stage switching control signal Su2+ is shown. As in the first low speed range VRL1, the first inverter 11 is controlled by active short circuit control in the second low speed range VRL2, so the first U-phase voltage command Vu1 ^** is a fixed value. In the second low speed range VRL2, the second inverter 12 is controlled by discontinuous pulse width modulation control. In the section where the second U-phase voltage command Vu2 ^** is "0" or "1", the first U-phase upper-side switching control signal Su1+ becomes a fixed value, and the switching element 3 (here, the second switching element 32) is turned on. state or fixed to the off state.

The waveform diagram of FIG. 33 shows the first U-phase voltage command Vu1 ^** , the second U-phase voltage command Vu2 ^** , the carrier CA, the first U-phase upper switching control signal Su1+, and the second U-phase voltage command Vu2** in the intermediate speed range VRM. An example with the upper stage switching control signal Su2+ is shown. As described above, both the first inverter 11 and the second inverter 12 are controlled by discontinuous pulse width modulation control in the third speed range VR3.

By the way, as shown in Table 3 below, in the intermediate speed range VRM, the rotary electric machine control device 1 controls both the first inverter 11 and the second inverter 12 by mixed pulse width modulation instead of discontinuous pulse width modulation control. It may be controlled by control (MX-PWM). Mixed pulse width modulation control is one of the control methods for controlling the inverter 10, and a plurality of pulses with different patterns are output in the first period T1 (see FIGS. 33 and 34), which is 1/2 period of the electrical angle. and the non-effective state continues in the second period T2 (see FIGS. 33 and 34) which is the remaining 1/2 period.

In the mixed pulse width modulation control, the switching control signal becomes ineffective during the second period T2, so that the loss of the inverter 10 is reduced, and the harmonic current due to switching is also reduced, thereby reducing the loss (iron loss) of the rotary electric machine 80. ) is also reduced. Thus, system losses can be reduced by implementing mixed pulse width modulation control.

FIG. 34 shows a first carrier CA1 that is the carrier CA of the first inverter 11, a second carrier CA2 that is the carrier CA of the second inverter 12, and a U-phase voltage common to the first inverter 11 and the second inverter 12. An example of a common U-phase voltage command Vu ^** , a first U-phase upper switching control signal Su1+, and a second U-phase upper switching control signal Su2+ is shown. Here, as the common U-phase voltage command Vu ^** , a mode is exemplified in which a voltage command of continuous pulse width modulation (space vector pulse width modulation) as illustrated in FIG. 31 is used. A voltage command of discontinuous pulse width modulation as illustrated may be used. When using continuous pulse width modulation (CPWM) voltage commands, mixed pulse width modulation control (MX-PWM) is called mixed continuous pulse width modulation control (MX-CPWM), and discontinuous pulse width modulation (DPWM) is called Mixed pulse width modulation control (MX-PWM) can be referred to as mixed continuous pulse width modulation control (MX-DPWM) when voltage commands are used. Mixed Continuous Pulse Width Modulation (MX-CPWM) will be described here as an example.

For example, the first carrier CA1 changes between "0.5<CA1<1", the second carrier CA2 changes between "0<CA2<0.5", and the voltage command (V ^** ) is , "0≤V ^** ≤1". By comparing the carrier CA (the first carrier CA1 and the second carrier VA2) with the voltage command (V ^** ), when the voltage command is equal to or higher than the carrier CA, the switching control signal becomes "1" and the voltage command becomes the carrier CA. If less, the switching control signal becomes "0".

As shown in FIG. 34, the amplitudes of the first carrier CA1 and the second carrier CA2 are half the amplitude allowed for the voltage command (V ^** ). In general pulse width modulation (see FIG. 33, etc.), the amplitude of carrier CA is equivalent to the amplitude allowed for voltage commands, and carrier CA in mixed pulse width modulation can be called a half carrier. By using such a half carrier, the half carrier and the voltage command (V ^** ) intersect in the first period T1, which is a half period of the electrical angle. are output. In the second period T2, which is the remaining 1/2 period, the half carrier and the voltage command (V ^** ) do not intersect, so the switching control signal is output so as to continue the ineffective state.

Although not shown in the drawings, depending on the waveform of the voltage command, even in the second period T2, there are cases where a pulse that is in a partially valid state is output as the switching control signal. For example, when ^using a voltage command (V ^** ) of discontinuous pulse width ^modulation , the second In some cases, a valid pulse is output during the period T2 as well. However, except for the vicinity of the amplitude center of the voltage command (V**), the ineffective state continues during the second period T2. In addition, the second period T2 is set only to the period in which the switching control signal is in an ineffective state (a period less than 1/2 period), and the switching control signal is set to a period other than the second period T2 (a period of 1/2 period or more) in one period. Once set, the mixed pulse width modulation can also be defined as follows. In mixed pulse width modulation control, a plurality of pulses with different patterns are output during a first period T1 that is equal to or longer than 1/2 period of the electrical angle, and an ineffective state is generated during a second period T2 that is the remainder of one period of the electrical angle. It can also be said that it is controlled to continue.

FIG. 35 illustrates a form of mixed pulse width modulation control (mixed continuous pulse width modulation control) different from FIG. The generated switching control signals are the same. FIG. 35 shows a first carrier CA1 that is the carrier CA of the first inverter 11, a second carrier CA2 that is the carrier CA of the second inverter 12, and a first U-phase voltage command that is the U-phase voltage command of the first inverter 11. An example of a command Vu1 ^** , a second U-phase voltage command Vu2 ^** that is a U-phase voltage command for the second inverter 12, a first U-phase upper switching control signal Su1+, and a second U-phase upper switching control signal Su2+ is shown. For example, the first carrier CA1 and the second carrier CA2 can change between "0.5<CA1<1", and the voltage command (V ^** ) can change between " ^0≤V** ≤1". is. The phases of the first carrier CA1 and the second carrier CA2 are different by 180 degrees (π). Also, the phases of the first U-phase voltage command Vu1 ^** and the second U-phase voltage command Vu2 ^** are different by 180 degrees (π).

As shown in FIG. 35, the amplitudes of the first carrier CA1 and the second carrier CA2 are half the amplitude allowed for the voltage command (V ^** ). Therefore, the carrier CA in the form shown in FIG. 35 is also a half carrier. By using such a half carrier, such a half carrier and the voltage command (V ^** ) intersect in the first period T1, which is 1/2 period (or 1/2 period or more) of the electrical angle. Therefore, a plurality of pulses with different patterns are output as switching control signals. In the second period T2, which is the remaining period of the cycle, the half carrier and the voltage command (V ^** ) do not intersect, so the switching control signal is output so that the ineffective state continues.

The form illustrated in FIG. 34 is a system of modulating with two half-carriers and a voltage command (V ^** ) as one common reference, and can be called a double-half-carrier/single-reference system. On the other hand, the form illustrated in FIG. 35 is a system that modulates with two half carriers and two voltage commands (V ^** ), and can be called a double half carrier/double reference system.

As shown in FIGS. 8 to 9, 30, and 33 to 35, when both the first inverter 11 and the second inverter 12 are switching-controlled, the first U-phase voltage command Vu1 ^** and the second U-phase voltage command Vu1** Vu2 ^** is a phase that differs by approximately 180 degrees. For example, the maximum amplitude of the U-phase voltage is "(4/3)E" and the maximum amplitude of the line voltage is "2E" (see also the vector diagrams of FIGS. 3 and 4). The first DC power supply 61 and the second DC power supply 62 are independent, and the first DC voltage E1 of the first DC power supply 61 and the second DC voltage E2 of the second DC power supply 62 are different values. There may be. For example, to be precise, the maximum amplitude of the U-phase voltage is "((2/3)E1)+(2/3)E2", but for ease of understanding, "E1= Let E2=E".

As described above, all power is supplied from one inverter 10 in the low speed range VRL, which is a relatively low power range where the modulation rate and rotation speed are relatively low. At this time, one inverter 10 is given a voltage command (V ^** ) so as to perform active short circuit control, and the other inverter 10 is given a normal voltage command (V ^** ). be done. In the intermediate speed region VRM, the high speed region VRH, and the ultra-high speed region VRSH, which are regions in which the modulation rate and rotation speed are high with respect to the low speed region VRL and the electric power is high with respect to the low speed region VRL, the two inverters 10 provide the same of power is supplied. At this time, the same voltage command (V ^** ) with a phase difference of 180 degrees (π) is given to both inverters 10 .

By the way, when the inverter 10 is switching-controlled, the pulsation component superimposed on the fundamental wave of the alternating current may generate noise in the audible frequency band. When the two inverters 10 are controlled by different control methods, pulsation occurs according to each control method, and noise in the audible frequency band may increase. Especially when the rotation speed of the rotating electric machine 80 is low, there is a high possibility that the frequency of the pulsation component (or its sideband frequency) is included in the audible frequency band. It is desirable that the control method of rotating electrical machine 80, that is, the control method of inverter 10, be appropriately set according to the operating conditions so that operation with high system efficiency and reduction of audible noise are compatible.

For example, the rotating electrical machine control device 1 may be provided with a control mode for the rotating electrical machine 80 that can be switched between a loss reduction priority mode and a noise reduction priority mode. For example, in the noise reduction priority mode, the rotary electric machine control device 1 controls both the first inverter 11 and the second inverter 12 by pulse width modulation in the low speed range VRL. Further, in the noise reduction priority mode, the rotary electric machine control device 1 controls both the first inverter 11 and the second inverter 12 by continuous pulse width modulation control in the first low speed range VRL1. In the speed range VRL2, both the first inverter 11 and the second inverter 12 may be controlled by discontinuous pulse width modulation control.

In the loss reduction priority mode, only one inverter 10 is driven in the low speed range VRL where the rotation speed of rotating electric machine 80 is relatively low, so that two inverters 10 do not emit noise in different frequency bands. However, since the output of one driven inverter 10 is increased, the noise energy is increased. In addition, in the low speed range VRL, the sound accompanying the running of the vehicle (driving sound such as the contact sound between the tires and the road surface) is also small, so the noise output from the one driven inverter 10 is in the audible frequency band. In some cases, noise may be more audible to the user.

For example, when the vehicle starts moving or decelerates toward a stop, the noise reduction priority mode is selected considering that noise in the audible frequency band is easily heard by the user. Preferably mode is selected. These modes may be selected by the user's operation (setting switch (including input from a touch panel or the like)).

In the noise reduction priority mode, the first inverter 11 and the second inverter 12 are controlled by the same control method in the low speed range VRL where the rotational speed of the rotating electric machine 80 is relatively low. Further, the phases of the currents of the two inverters 10 that pass the currents through the stator coils 8 differ by approximately 180 degrees. If the two inverters 10 are controlled by the same control method, the phases of the currents, including the pulsating component, will differ by approximately 180 degrees. Therefore, at least part of the pulsation components can cancel each other, and noise in the audible frequency band can be reduced.

FIG. 38 shows, as a comparative example, an example of a control region of a rotating electrical machine in a one-inverter system in which three-phase stator coils 8 are connected at a neutral point. This inverter is controlled, for example, by continuous pulse width modulation control in a first region VR11, by discontinuous pulse width modulation control in a second region VR13, and by a rectangular pulse width modulation control in a third region VR14, as shown in Table 4 below. Controlled by wave control.

Here, the modulation rate "Y" is a value larger than the modulation rate "X" exemplified in Tables 2 and 3, and is the theoretical upper limit of the modulation rate by continuous pulse width modulation (space vector pulse width modulation). (approximately 0.707), and considering the dead time, it is set to, for example, about 0.5 to 0.6.

As described above, in the present embodiment, the intermediate speed region VRM is set on the low speed side of the region corresponding to the second region VR13, and the high speed region VRH is set on the high speed side. Modulation control is performed. The special pulse width modulation control reduces the loss of inverter 10 in the operating region where high output is required, and also reduces the harmonic current due to switching, thereby reducing the loss (iron loss) of rotating electric machine 80 . In other words, system losses can be reduced by performing special pulse width modulation control. Further, by setting the low speed range VRL in the range corresponding to the first range VR11, it is possible to reduce the system loss even in the operation range where the required output is low. Further, in the low speed range VR1, as described above, the loss reduction priority mode and the noise reduction priority mode may be switched as appropriate. In the loss reduction priority mode, it is possible to reduce the loss of the entire system, and in the noise reduction priority mode, it is possible to reduce the noise as well as the loss.

[Outline of embodiment]
An overview of the rotary electric machine control device (1) described above will be briefly described below.

As one aspect, a rotary electric machine control device ( 1), the first inverter (11) is connected to one end of the multi-phase open winding (8) to convert power between direct current and multi-phase alternating current, and the second inverter ( 12) is connected to the other end of the multi-phase open winding (8) to convert power between direct current and multi-phase alternating current, the first inverter (11) and the second inverter ( 12) can be controlled by a plurality of control methods with different switching patterns, and can be controlled by the control methods that are independent of each other; pulse width modulation control in which a pulse is output, and rectangular wave control in which one pulse is output in one cycle of the electrical angle, one of the first inverter (11) and the second inverter (12) The inverter (10) is controlled by the rectangular wave control, and the other inverter (10) is controlled by the special pulse width modulation control which is one of the pulse width modulation controls. The modulation control is the control method in which the switching pattern is based on the difference between the switching pattern by the pulse width modulation control when the target voltage is generated in the open winding (8) and the switching pattern by the rectangular wave control. be.

According to this configuration, one of the two inverters (10) is subjected to rectangular wave control, thereby reducing the number of switching times of the one inverter (10) and reducing the switching loss. can. In addition, the other inverter (10) on the side not subjected to square wave control is controlled by special pulse width modulation control. In the special pulse width modulation control, the switching pattern based on the difference between the switching pattern by the pulse width modulation control when the target voltage is generated in the open winding (8) and the switching pattern by the rectangular wave control is used to control the other inverter. (10) is controlled. Therefore, even if one inverter (10) is controlled by rectangular wave control, the rotary electric machine (80) can be driven smoothly by combining the pulse width modulation control of the other inverter. In general, system loss can be reduced and the rotating electric machine (80) can be smoothly controlled in a relatively high rotation operating region where square wave control is applied. That is, according to this configuration, it is possible to appropriately control the two inverters provided at both ends of the open winding.

Here, when generating a target voltage in the open winding (8), a voltage command for generating a switching pattern of one of the inverters (10) controlled by the rectangular wave control is defined as a rectangular wave voltage command, A voltage command that is 180 degrees out of phase with the rectangular wave voltage command, and is a voltage that generates a switching pattern of the other inverter (10) controlled by the pulse width modulation control when generating the target voltage. The command is a voltage command for pulse width modulation, the difference between the voltage command for rectangular wave and the voltage command for pulse width modulation is a system voltage command that is the voltage command for the entire two inverters (10), and the amplitude center is matched. The difference between the system voltage command and the rectangular wave voltage command in the state of being switched is used as a special pulse width modulation voltage command, and the special pulse width modulation control performs switching based on the special pulse width modulation voltage command. It is preferred that the control method is that patterns are generated.

According to this configuration, when the rotating electrical machine (80) is smoothly driven by combining the rectangular wave control and the pulse width modulation control, the voltage command in the pulse width modulation control can be optimized. According to experiments and simulations by the inventors, it has been confirmed that ripples are generated in the current flowing through the open winding (8) when the rectangular wave control and the pulse width modulation control are simply combined. However, it has been confirmed that such ripples are suppressed by special pulse width modulation control. The voltage command for generating the switching pattern in the special pulse width modulation control is based on the system voltage command, which is the overall voltage command when the square wave control and the pulse width modulation control are combined. It is set as a difference from the wave voltage command. Therefore, it is possible to reduce the ripple as described above while generating the target voltage in the open winding as in the case of combining the rectangular wave control and the pulse width modulation control.

Further, as a control region (R) of the rotating electrical machine (80), a low speed range (VRL) and a rotation speed of the rotating electrical machine (80) at the same torque (T) are higher than the low speed range (VRL). A high speed range (VRH) is set, and the rotary electric machine control device (1) preferably executes the target control in the high speed range (VRH).

Generally, in such a high speed range (VRH), the inverter (10) is controlled by a control method using pulse width modulation, which is a modulation method with a high modulation rate. In the target control, one inverter (10) of the two inverters (10) is subjected to rectangular wave control, so switching loss of the one inverter (10) can be reduced. According to this configuration, it is possible to improve system efficiency in a high speed range (VRH) where a relatively high output is required of the inverter (10).

Further, the first inverter (11) and the second inverter (12) each have an AC one-phase arm (3A) formed by a series circuit of an upper switching element (3H) and a lower switching element (3L). The pulse width modulation control includes, as the control method, continuous pulse width modulation control for continuously performing pulse width modulation on all of the arms (3A) of the plurality of phases, and a part of the arms of the plurality of phases (3A) includes a discontinuous pulse width modulation control that performs pulse width modulation including a period in which the switching element (3) is fixed in the ON state or the OFF state, and the high speed region (VRH) includes the second A first high speed region (VRH1) and a second high speed region (VRH2) in which the rotational speed of the rotating electric machine (80) at the same torque (T) is higher than that of the first high speed region (VRH1) are set, In the first high speed region (VRH1), the rotating electric machine control device (1) controls one of the first inverter (11) and the second inverter (12) (10) as the target control. rectangular wave control, the other inverter (12) is controlled by special continuous pulse width modulation which is the special pulse width modulation control based on the continuous pulse width modulation control, and the second object control is executed; In the high speed range (VRH2), the rotating electric machine control device (1) controls the inverter (10), which is one of the first inverter (11) and the second inverter (12), as the target control by the rectangular wave control. and the other inverter (10) is controlled by special discontinuous pulse width modulation, which is the special pulse width modulation control based on the discontinuous pulse width modulation control.

The maximum modulation rate with discontinuous pulse width modulation control is greater than the maximum modulation rate with continuous pulse width modulation control. The second high speed region (VRH2) is a control region (R) in which the rotation speed of the rotating electric machine (80) is higher than that of the first high speed region (VRH1) at the same torque (T). It is preferable that the second high speed region (VRH2) is modulated at a higher modulation rate than the first high speed region (VRH1). Special continuous pulse width modulation control based on continuous pulse width modulation is executed in the first high speed region (VRH1), and special continuous pulse width modulation control based on discontinuous pulse width modulation is executed in the second high speed region (VRH2). Thus, the rotating electric machine (80) can be driven appropriately over the entire high speed range (VRH).

Further, as a control region (R) of the rotating electrical machine (80), a low speed range (VRL) and a rotation speed of the rotating electrical machine (80) at the same torque (T) are higher than the low speed range (VRL). A high speed range (VRH) is set, and the rotary electric machine control device (1) executes the target control in the high speed range (VRH). In the low speed range, the first inverter and the second inverter is controlled by the pulse width modulation control, in the high speed range (VRH), the modulation frequency ( _FCA ) higher than the modulation frequency ( _FCA ) in the pulse width modulation control, Preferably, said special pulse width modulation control is performed.

According to studies by the inventors, it has been found that the voltage command in the special pulse width modulation control has a large inflection point at which the value of the voltage command sharply increases or decreases every half cycle of the electrical angle. According to experiments and simulations by the inventors, it has been confirmed that ripples occur in the current flowing through the open winding (8) at a phase near this point of inflection. This is because the modulation frequency ( _FCA ) does not have resolution that can respond to a sharp increase or decrease in the value of the voltage command in the phase near the inflection point. According to this configuration, the special pulse width modulation control is executed with the modulation frequency ( _FCA ) higher than the modulation frequency ( _FCA ) in the pulse width modulation control. Therefore, the modulation frequency ( _FCA ) can respond to a rapid increase or decrease in the value of the voltage command in the phase near the inflection point, and ripples as described above can be reduced.

Further, a super high speed range (VRSH) is further set in which the rotating speed of the rotating electrical machine (80) is higher than the high speed range (VRH) at the same torque (T), and in the super high speed range, the rotating electrical machine control Preferably, the device (1) controls said inverter (10), both said first inverter (11) and said second inverter (12), by said square wave control.

In the high speed range (VRH), one inverter (10) is controlled by square wave control and the other inverter (10) by special pulse width modulation. By shifting the control method of the other inverter (10) to rectangular wave control, the control method is smoothly changed from target control in the high speed range (VRH) to rectangular wave control in the super high speed range (VRSH). be able to. That is, according to this configuration, the rotary electric machine 80 can be appropriately driven over the high speed range VRH and the super high speed range VRSH.

Further, the first inverter (11) and the second inverter (12) each have an AC one-phase arm (3A) formed by a series circuit of an upper switching element (3H) and a lower switching element (3L). The control method includes turning on the upper switching elements (3H) of the arms (3A) of all the multiple phases or turning on the lower switching elements (3L) of the arms (3A) of all the multiple phases. ) is turned on, and in the low speed range (VRL), the rotary electric machine control device (1) controls one of the first inverter (10) and the second inverter (12). It is preferable to execute target low speed range control in which the inverter (10) of one is controlled by the active short circuit control and the other inverter (10) is controlled by the pulse width modulation control.

By executing the target low-speed range control, the rotary electric machine (80) is substantially driven by only one inverter (10) out of the two inverters (10). Since one inverter (10) does not perform switching operation, it is possible to drive the rotating electric machine (80) while suppressing the loss of the entire system.

Further, the first inverter (11) and the second inverter (12) each have an AC one-phase arm (3A) formed by a series circuit of an upper switching element (3H) and a lower switching element (3L). The pulse width modulation control includes, as the control method, continuous pulse width modulation control for continuously performing pulse width modulation on all of the arms (3A) of the plurality of phases, and a part of the arms of the plurality of phases (3A) includes a discontinuous pulse width modulation control that performs pulse width modulation including a period in which the switching element (3) is fixed in the ON state or the OFF state, and the low speed region (VRL) includes the second A first low speed region (VRL1) and a second low speed region (VRL2) in which the rotational speed of the rotating electric machine (80) at the same torque (T) is higher than that of the first low speed region (VRL1) are set, In the first low speed range (VRL1), the rotating electric machine control device (1) controls one of the first inverter (11) and the second inverter (12) (10) as the target low speed range control. is controlled by the active short circuit control, the other inverter (10) is controlled by the continuous pulse width modulation control, and in the second low speed region (VRL2), rotation An electric machine control device (1) controls one of the first inverter (11) and the second inverter (12) (10) by the active short circuit control as the target low speed range control, It is preferable to execute a second target low speed range control in which the inverter (10) of is controlled by the discontinuous pulse width modulation control.

The maximum modulation rate with discontinuous pulse width modulation control is greater than the maximum modulation rate with continuous pulse width modulation control. The second low speed range (VRL2) is a control range (R) in which the rotation speed of the rotating electric machine (80) is higher than that of the first low speed range (VRL1) at the same torque (T). It is preferable that the second low speed region (VRL2) is modulated at a higher modulation rate than the first low speed region (VRL1). A first target low speed range control using continuous pulse width modulation control is executed in the first low speed range (VRL1), and a second target low speed range using discontinuous pulse width modulation is executed in the second low speed range (VRL2). By executing range control, the rotating electric machine (80) can be driven appropriately over the entire low speed range (VRL).

In addition, the rotating electric machine control device (1) controls one of the first inverter (10) and the second inverter (12) by the active short circuit control in the low speed range (VRL). and the other inverter (10) is controlled by the pulse width modulation control, the control method for controlling the first inverter (11) and the second inverter (12). and the control method for controlling are alternately exchanged according to predetermined conditions.

By switching the control method, consumption of only one of the first inverter (11) and the second inverter (12) is suppressed. Further, when the first inverter (11) and the second inverter (12) are connected to independent DC power supplies (6), the DC power supply (61) and the second inverter (61) connected to the first inverter (11) It is possible to suppress an increase in power consumption of only one of the DC power supplies (62) connected to the two inverters (12). Here, it is preferable that the prescribed condition is, for example, a certain period of time or the power consumption of the DC power supply (6).

Further, the first inverter (11) and the second inverter (12) each have an AC one-phase arm (3A) formed by a series circuit of an upper switching element (3H) and a lower switching element (3L). In the pulse width modulation control, as the control method, pulse width modulation is performed including a period for fixing the switching element (3) in the ON state or the OFF state for the arm (3A) of a part of the multiple phases. In the control region (R), the rotation speed of the rotating electric machine (80) at the same torque (T) is higher than the low speed region (VRL) and the high speed region ( An intermediate speed range (VRM) lower than VRH) is further set, and in the intermediate speed range (VRM), the rotating electric machine control device (1) controls the first inverter (11) and the second inverter (12). Preferably, both said inverters (10) are controlled by said discontinuous pulse width modulation control.

According to this configuration, a low speed region (VRL) controlled by low speed target control using active short circuit control and pulse width modulation control, and a low speed region (VRL) controlled by target control using square wave control and special pulse width modulation control Both inverters (10) are controlled by discontinuous pulse width modulation control in the control region (R) between the high speed region (VRH). As a result, the rotating electric machine (80) can be driven smoothly over a wide control range from the low speed range (VRL) through the medium speed range (VRM) to the high speed range (VRH).

In the above control method, a plurality of pulses with different patterns are output in the first period (T1), which is 1/2 period of the electrical angle, and non-uniform pulses are output in the second period (T2), which is the remaining 1/2 period. Mixed pulse width modulation control controlled so that the effective state continues is included, and the rotating electric machine control device (1) controls the first inverter (11) and the second inverter ( 12) are preferably controlled by the mixed pulse width modulation control instead of the discontinuous pulse width modulation control.

Mixed pulse width modulation control is a control method that combines a period of pulse width modulation and a period of non-modulation (fixed state) approximately every half cycle during one cycle of the electrical angle. In other words, since the inverter (10) does not perform switching operation during approximately half of the driving time, the switching loss is reduced and the system loss is reduced.

In addition, the boundaries of the respective control regions (R) are defined by the rotational speed of the rotating electrical machine (80) corresponding to the torque of the rotating electrical machine (80) and the effective line voltage of the multi-phase AC voltage with respect to the DC voltage. It is preferable that it is set according to at least one of the ratio of the values.

The operating conditions of the rotating electric machine (80) are often defined by the relationship between rotational speed and torque. When the rotating electrical machine control device (1) changes the control method for controlling the first inverter (11) and the second inverter (12) based on the rotation speed, which is one parameter, the operating conditions of the rotating electrical machine (80) The rotary electric machine (80) can be driven and controlled with high efficiency in accordance with . Further, for example, when a high output (high rotational speed or high torque) is required for the rotating electric machine (80), the voltage-type inverter increases the DC voltage or the rate at which the DC voltage is converted to AC voltage. This requirement is realized by increasing If the DC voltage is constant, this requirement can be met by increasing the rate at which the DC voltage is converted to AC voltage. This ratio can be expressed as the ratio of the effective value of the three-phase AC power to the DC power (in the case of a voltage-type inverter, it is equivalent to the ratio of the effective value of the line voltage of the three-phase AC voltage to the DC voltage). . There are various control methods for controlling the inverter (10), ranging from low to high ratios. By changing the control method based on the ratio of the effective values of the line voltages of the multi-phase AC voltages to the DC voltage determined according to the requirements of the rotating electrical machine (80), the operating conditions of the rotating electrical machine (80) Therefore, the rotating electric machine (80) can be driven and controlled with high efficiency.

Further, one of the first inverter (11) and the second inverter (12), the one inverter (10) is configured using a first switching element (31), and the other inverter (10) is , a second switching element (32) having a switching loss smaller than that of the first switching element (31) at the time of transition between an off state and an on state, and controlled by the special pulse width modulation control; It is preferable that the inverter (10) that is connected to the inverter (10) is configured using the second switching element (32).

An inverter (10) controlled by square wave control will switch less than an inverter (10) controlled by special pulse width modulation control. According to this configuration, by causing the inverter (10) configured using the second switching element (32) with relatively small switching loss to switch more, in a high speed range (VRH) where high output is required. It is possible to suppress the loss of the entire system.

One of the first inverter (10) and the second inverter (12) is controlled by the active short circuit control, and the other inverter (10) is controlled by the pulse width modulation control. When the target low speed range control to be performed is executed, one of the first inverter (11) and the second inverter (12), the inverter (10), uses the first switching element (31) and the other inverter (10) is configured using a second switching element (32) having a switching loss smaller than that of the first switching element (31) at the time of transition between an off state and an on state. and the inverter controlled by the pulse width modulation control is configured using the second switching element.

In the low speed range VRL, one inverter 10 (here, the first inverter 11) of the first inverter 11 and the second inverter 12 is controlled by active short circuit control, and the other inverter 10 (here, the second inverter 12) is controlled by active short circuit control. ) is executed by pulse width modulation control. That is, substantially only one of the two inverters 10 (for example, the second inverter 12) drives the rotating electric machine 80 . Since one inverter 10 does not perform a switching operation, it is possible to drive the rotary electric machine 80 while suppressing the loss of the entire system.

Also, the first switching element (31) is preferably Si-IGBT or Si-MOSFET, and the second switching element (32) is preferably SiC-MOSFET or GaN-MOSFET.

For example, silicon carbide (SiC) has a dielectric breakdown electric field strength higher than that of silicon (Si), so that a drift layer can be formed with a high impurity concentration and a thin film thickness when a high withstand voltage power device is configured. . Since most of the resistance component of the high voltage power device is the resistance of the drift layer, SiC devices have a lower on-resistance per unit area than Si devices. That is, SiC devices can reduce switching loss compared to Si devices. The same applies to devices using gallium nitride (GaN). Therefore, when the first switching element (31) is a Si device, by using a SiC device or a GaN device as the second switching element (32), the switching loss is relatively reduced compared to the first switching element (31). The inverter (10) can be constructed using a small second switching element (32).

Reference Signs List 1: rotary electric machine control device 3: switching element 3A: arm 3H: upper switching element 3L: lower switching element 8: stator coil (open winding)
10: Inverter 11: First inverter 12: Second inverter 80: Rotating electric machine R: Control region T: Torque T1: First period T2: Second period VRH: High speed region VRH1: First high speed region VRH2: Second High speed range VRL: Low speed range VRL1: First low speed range VRL2: Second low speed range VRM: Intermediate speed range VRSH: Super high speed range

Claims (15)

A rotary electric machine control device that drives and controls a rotary electric machine having open windings of a plurality of phases that are independent of each other via a first inverter and a second inverter,
The first inverter is connected to one end of the multi-phase open winding and converts power between direct current and multi-phase alternating current,
the second inverter is connected to the other end of the multi-phase open winding and converts power between direct current and multi-phase alternating current;
each of the first inverter and the second inverter can be controlled by a plurality of control methods with different switching patterns, and can be controlled by the control methods independent of each other;
The control method includes pulse width modulation control in which a plurality of pulses with different patterns are output in one cycle of electrical angle, and rectangular wave control in which one pulse is output in one cycle of electrical angle,
One of the first inverter and the second inverter is controlled by the rectangular wave control, and the other inverter is controlled by special pulse width modulation control, which is one of the pulse width modulation controls. ,
The special pulse width modulation control is the control method in which the switching pattern is based on the difference between the switching pattern by the pulse width modulation control when the target voltage is generated in the open winding and the switching pattern by the square wave control. A rotary electric machine control device. when a target voltage is generated in the open winding, a voltage command for generating a switching pattern of one of the inverters controlled by the rectangular wave control is a rectangular wave voltage command;
A voltage command that is 180 degrees out of phase with the rectangular wave voltage command, and is a voltage command that generates a switching pattern of the other inverter controlled by the pulse width modulation control when generating the target voltage. As a voltage command for width modulation,
The difference between the voltage command for rectangular wave and the voltage command for pulse width modulation is defined as a system voltage command that is a voltage command for the entire two inverters,
The difference between the system voltage command and the rectangular wave voltage command with the amplitude centers aligned as a special pulse width modulation voltage command,
2. The rotary electric machine control device according to claim 1, wherein said special pulse width modulation control is said control method in which a switching pattern is generated based on said voltage command for special pulse width modulation. A low-speed region and a high-speed region in which the rotation speed of the rotating electrical machine is higher than that of the low-speed region at the same torque are set as the control region of the rotating electrical machine,
3. The rotary electric machine control device according to claim 1, wherein said target control is executed in said high speed range. Each of the first inverter and the second inverter has an arm for one AC phase composed of a series circuit of an upper-stage switching element and a lower-stage switching element,
The pulse width modulation control includes, as the control method, continuous pulse width modulation control for continuously performing pulse width modulation on all of the arms of the plurality of phases, and turning on the switching elements of some of the arms of the plurality of phases. Or discontinuous pulse width modulation control that performs pulse width modulation including a period fixed in the off state,
Within the high-speed range, a first high-speed range and a second high-speed range in which the rotation speed of the rotating electric machine at the same torque is higher than that of the first high-speed range are set,
In the first high-speed region, as the target control, one of the first inverter and the second inverter is controlled by the rectangular wave control, and the other inverter is controlled by the continuous pulse width modulation control. Execute the first target control controlled by special continuous pulse width modulation which is special pulse width modulation control,
In the second high-speed region, as the target control, one of the first inverter and the second inverter is controlled by the rectangular wave control, and the other inverter is based on the discontinuous pulse width modulation control. 4. The rotary electric machine control device according to claim 3, which executes a second target control that is controlled by special discontinuous pulse width modulation, which is said special pulse width modulation control. In the low speed range, at least one of the first inverter and the second inverter is controlled by the pulse width modulation control,
5. The rotary electric machine control device according to claim 3, wherein in said high speed range, said special pulse width modulation control is executed with a modulation frequency higher than that in said pulse width modulation control. An ultra-high speed range is further set in which the rotation speed of the rotating electrical machine at the same torque is higher than that of the high speed range,
6. The rotary electric machine control device according to claim 3, wherein in said ultra-high speed region, said inverters of both said first inverter and said second inverter are controlled by said rectangular wave control. Each of the first inverter and the second inverter has an arm for one AC phase composed of a series circuit of an upper-stage switching element and a lower-stage switching element,
The control method further includes active short circuit control that turns on the upper switching elements of the arms of all of the multiple phases or turns on the lower switching elements of the arms of all of the multiple phases,
In the low-speed region, target low-speed region control is executed in which one of the first inverter and the second inverter is controlled by the active short circuit control, and the other inverter is controlled by the pulse width modulation control. The rotary electric machine control device according to any one of claims 3 to 6, wherein Each of the first inverter and the second inverter has an arm for one AC phase composed of a series circuit of an upper-stage switching element and a lower-stage switching element,
The pulse width modulation control includes, as the control method, continuous pulse width modulation control for continuously performing pulse width modulation on all of the arms of the plurality of phases, and turning on the switching elements of some of the arms of the plurality of phases. Or discontinuous pulse width modulation control that performs pulse width modulation including a period fixed in the off state,
Within the low-speed region, a first low-speed region and a second low-speed region in which the rotation speed of the rotating electrical machine at the same torque is higher than that of the first low-speed region are set,
In the first low speed range, as the target low speed range control, one of the first inverter and the second inverter is controlled by the active short circuit control, and the other inverter is controlled by the continuous pulse width modulation. Execute the first target low speed range control controlled by the control,
In the second low speed range, as the target low speed range control, one of the first inverter and the second inverter is controlled by the active short circuit control, and the other inverter is controlled by the discontinuous pulse width. 8. The rotary electric machine control device according to claim 7, which executes second target low speed range control controlled by modulation control. 9. The electric rotating machine according to claim 7, wherein in said low speed range, said control method for controlling said first inverter and said control method for controlling said second inverter are alternately switched according to a predetermined condition. Control device. Each of the first inverter and the second inverter has an arm for one AC phase composed of a series circuit of an upper-stage switching element and a lower-stage switching element,
The pulse width modulation control includes, as the control method, discontinuous pulse width modulation control in which pulse width modulation is performed including a period in which the switching elements of some of the arms of the multiple phases are fixed in an on state or an off state. be,
As the control region, an intermediate speed region is further set in which the rotation speed of the rotating electric machine is higher than the low speed region and lower than the high speed region at the same torque,
10. The rotary electric machine control device according to claim 3, wherein in said intermediate speed range, said inverters of both said first inverter and said second inverter are controlled by said discontinuous pulse width modulation control. In the control method, a plurality of pulses with different patterns are output in the first period, which is 1/2 period of the electrical angle, and the non-effective state continues in the second period, which is the remaining 1/2 period. mixed pulse width modulation control,
11. The rotary electric machine control device according to claim 10, wherein in said intermediate speed range, both said first inverter and said second inverter are controlled by said mixed pulse width modulation control instead of said discontinuous pulse width modulation control. The boundary of each of the control regions is determined according to at least one of the rotation speed of the rotating electrical machine according to the torque of the rotating electrical machine and the ratio of the effective value of the line voltage of the multi-phase AC voltage to the DC voltage. The rotary electric machine control device according to any one of claims 3 to 11, which is set. One of the first inverter and the second inverter is configured using a first switching element, and the other inverter has a switching loss at the time of transition between an off state and an on state. configured using a second switching element smaller than the first switching element,
13. The rotary electric machine control device according to claim 1, wherein said inverter controlled by said special pulse width modulation control is configured using said second switching element. One of the first inverter and the second inverter is configured using a first switching element, and the other inverter has a switching loss at the time of transition between an off state and an on state. configured using a second switching element smaller than the first switching element,
10. The rotary electric machine control device according to claim 7, wherein said inverter controlled by said pulse width modulation control is configured using said second switching element. 15. The rotary electric machine control device according to claim 13, wherein said first switching element is Si-IGBT or Si-MOSFET, and said second switching element is SiC-MOSFET or GaN-MOSFET.

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